CONNECTED-WORLD STUDY | RESEARCH REPORT

THE CONNECTED WORLD

Gold, Salt, Silk, Spices, Grain, Enslaved Labour, Disease, Technologies and Religious Ideas

A comparative history of the Indian Ocean, Sahara, Silk Roads and Atlantic worlds

Author & Researcher: Shubham Phougat

Research synthesis and comparative analysis | 13 October 2026

Shubham Phougat • Connected-World Study | 1

Abstract

This report reconstructs connected-world history as a set of overlapping, changing networks rather than as four separate routes or a single, seamless world economy. It traces goods, people, pathogens, technologies and religious ideas through the Indian Ocean, trans-Saharan corridors, the Silk Roads and the Atlantic system, with attention to chronology, regional agency, intermediary traders, political power and the unequal human consequences of exchange. Its central argument is that connectivity was built through relays: local producers, caravan operators, sailors, port cities, brokers, states, diasporas, financiers and religious institutions linked places that rarely dealt with one another directly. Goods and ideas could travel far, but they did not travel at equal speed, scale or risk. [1-8]

The report compares high-value goods such as silk, pepper and gold with necessities such as salt and grain; distinguishes slavery in different regions rather than treating it as one uniform institution; and analyses disease and technology transfer without assuming that every movement has one route or one cause. The Atlantic world after 1492 did not simply replace older networks: it reoriented them, intensified coercive plantation production, expanded oceanic imperial competition and linked American crops and bullion to Afro-Eurasian markets. [9-18]

Scope and method

The study ranges from antiquity to the nineteenth century, with a few deep-time references where the evidence matters. It uses archaeological finds, inscriptions, papyri, travel accounts, shipping and voyage databases, and modern scholarship. Citation numbers in the text correspond to the selected bibliography at the end. Broad claims are marked with uncertainty where quantities or causal pathways remain contested. The word ‘route’ is used as shorthand: historically, most exchange depended on networks and repeated transfers, not one merchant carrying one object from end to end.

Executive findings

• The routes were systems of connected segments. The same port or market could link sea lanes, river valleys, caravan paths, fiscal systems and religious institutions; no single corridor explains its entire history. [1-4, 7-10]
• Intermediaries were not mere obstacles between producer and consumer. They supplied finance, credit, local knowledge, security, warehousing, translation and the ability to manage risk. Their margins helped determine who profited. [3-6, 19-21]
• High-value goods travelled furthest, but staple goods mattered more to daily life. Salt and grain can be less visible in narratives dominated by gold and spices even when their regional volume and political importance were immense. [11-13, 22]
• The commodity map was regionally specific: West African gold and Saharan salt; South Asian pepper and cotton textiles; Chinese silk and ceramics; Southeast Asian cloves and nutmeg; African ivory and gold; Mediterranean and Egyptian grain; and, after 1492, American silver, sugar, tobacco, maize and potatoes. [5, 8, 11, 14-18, 23-25]
• Slavery existed in all four broad worlds, but institutions, scale, legal status, labour uses, demographic profiles and racial ideologies differed. Atlantic plantation slavery developed into an unusually large, hereditary and racialised system tied to colonial states, shipping finance and commodity production. [15- 18, 26-29]
• Disease moved through ecological and human networks, but ‘trade caused a pandemic’ is usually too simple. Ancient DNA identifies a major ancestor of the Black Death-associated plague lineage in

fourteenth-century Central Asia; the subsequent spread depended on multiple overland, maritime, animal and human processes. [30]

• Technologies rarely travelled as isolated inventions. Paper, printing, gunpowder, navigational knowledge, shipbuilding methods, textile skills, mills, crop systems and financial techniques were adapted locally; invention, diffusion and independent innovation must be distinguished. [2, 5, 19, 31]
• Religions travelled through merchants, migrants, monks, scholars, pilgrims, dynasties and family networks, but local rulers and communities transformed them. Shared belief could support trust, yet trade did not automatically produce conversion or tolerance. [2-4, 8, 10, 32]
• A more connected world was not necessarily a more equal one. Exchange could enrich ports, cities and states while exposing producers, conquered peoples, enslaved workers and Indigenous communities to extraction, forced movement, famine, violence and epidemic disease. [15-18, 26-30]
• The most defensible long-run picture is neither ‘Europe created globalisation’ nor ‘the whole world had already become one market.’ Afro-Eurasian interregional systems predated Atlantic expansion; the post-1500 Atlantic transformation then reshaped their scale, coercive institutions and global balance of power. [6, 9, 16-18]

Contents

1. How to think about connected-world history
2. The four broad systems and their historical rhythms
3. Indian Ocean: monsoons, ports and mobile communities
4. Sahara: salt, gold, caravans and the Sahel
5. Silk Roads: an inland web of intermediaries
6. Atlantic world: forced migration, plantations and imperial commerce
7. Following commodities across regions
8. Disease and demographic shock
9. Technologies, knowledge and infrastructure
10. Religious ideas and cultural translation
11. Labour, power, credit and unequal gains
12. Five comparative case studies
13. What the evidence can and cannot show
14. Conclusion: connected, not uniform Appendix A. Comparative matrix Appendix B. Selected chronology Appendix C. Glossary Selected bibliography and digital sources

1. How to think about connected-world history

From roads to networks

The phrase ‘Silk Road’ is memorable but can mislead if it encourages the image of a single road joining China to Rome. UNESCO stresses that the name is a modern label for plural land and maritime routes, along which silk was only one of many commodities. The same warning applies to the trans-Saharan, Indian Ocean and Atlantic ‘routes’: they were overlapping lanes and commercial spaces, not fixed highways. [1,2]

A useful unit of analysis is the commodity chain: production, collection, inland transport, storage, customs, finance, maritime or caravan movement, wholesale exchange, retailing and consumption. A bag of pepper could pass through upland collectors, regional brokers, a coastal emporium, a shipowner, a Red Sea or Persian Gulf trader, a Mediterranean port and several financiers before reaching a consumer. A shipment might change hands without any single participant knowing its full geography. [3,5,19]

Connectivity has several dimensions

Three distinctions that prevent false conclusions

• Contact is not the same as integration. Archaeological imports or a foreign coin can prove contact or circulation, but not necessarily direct voyages, mass migration or a unified market.
• Diffusion is not the same as invention. A tool or technique may appear in a new region after contact; that does not by itself show where it was invented, who transmitted it, or whether its adoption was immediate.
• Trade is not the same as consent. A commercial network can connect voluntarily trading partners and simultaneously carry captives, coerced workers, tribute, colonial monopolies or goods produced under brutal labour regimes. Central thesis: the connected world was made by moving things, but also by building institutions that reduced some kinds of risk while transferring other risks onto less powerful people.

2. The four broad systems and their historical rhythms

These networks overlapped in time but did not have identical peaks. Dates below are broad periods of intensification, not start-or-stop dates: sea lanes and caravan paths were often much older than surviving written evidence suggests.

Janet Abu-Lughod’s study of the thirteenth-century world system is a key corrective to a Europe-only narrative: by 1250-1350, several regional subsystems from northwest Europe to China were linked, though not uniformly and not with the density of modern globalisation. This does not mean the world was one market; it means European expansion entered pre-existing commercial worlds and subsequently changed them. [6]

3. Indian Ocean: monsoons, ports and mobile communities

The monsoon as an economic institution

Unlike an overland trail, the Indian Ocean’s key infrastructure was seasonal wind. In the Arabian Sea, monsoon winds reverse direction during the year, offering predictable windows for sailing but also creating waiting periods, exposure to weather and the need for port-based provisioning. Sailors’ knowledge of seasonal winds shaped departure dates, ship capacity, cargo finance and merchant residence. The ocean was not an empty gap between continents: it was a connected commercial space that linked East Africa, Arabia, western and southern India, Sri Lanka, Southeast Asia and China. [3,5,19]

Goods and routes

• From South Asia: pepper, cotton textiles, beads, precious stones, rice and other goods, with production and export hubs changing over time. Roman-period pepper trade drew on the Western Ghats and coastal emporia; the Muziris papyrus and classical texts illuminate shipping, loans, customs and tax procedures. [4,5,7]
• From Southeast Asia: cloves, nutmeg, mace, aromatic woods and resins, together with forest and marine products. The Moluccas were especially important for cloves and nutmeg; these spices were already moving through Asian networks before European vessels entered the Indian Ocean at the end of the fifteenth century. [23]
• From East Asia: silk, ceramics and other manufactures; from the western Indian Ocean: horses, glass, dates, textiles, metals, ivory and gold. Cargoes were mixed and route-dependent, not a fixed list shipped every season. [1,3,6]
• From East Africa and inland southern Africa: gold and ivory entered coastal circuits through Swahili ports. Finds of imported ceramics and coins inland demonstrate the reach of exchange, but do not imply that coastal merchants controlled every inland producer. [8,24]

Ports, diasporas and local agency

Ports such as Aden, Hormuz, Cambay, Calicut, Quilon, Melaka, Guangzhou, Kilwa and Mombasa operated as nodes of translation. Merchants needed local language skills, trustworthy agents, storage, credit and knowledge of rulers’ tolls. Diasporas could lower transaction costs by supplying kinship ties and dispute resolution, yet merchants did not trade only with co-religionists. Scholarship on western Indian Ocean networks emphasizes geography, ethnicity and religious affiliation as intersecting sources of cohesion, not one universal merchant identity. [3,6,10]

The Indo-Roman example

The first centuries CE show how a maritime commodity chain could link inland production to distant consumption. The Periplus of the Erythraean Sea, Roman-era literary references and the Muziris papyrus indicate shipping schedules, cargoes, loans and customs duties in the South India-Red Sea-Mediterranean connection. Pepper did not simply travel from ‘India to Rome’: it was gathered in ecological zones, moved through multiple local intermediaries, purchased or financed at ports, transported across the Arabian Sea and Red Sea, and passed through the Egyptian and Mediterranean fiscal systems. Roman coin finds in South Asia are evidence of monetary and commercial connections, but coins alone do not tell us whether all were used as currency, melted, hoarded or re-circulated. [4,5,7]

From commerce to empire

Portuguese, Dutch and English expansion after 1498 brought armed shipping, forts, monopolistic ambitions, treaty-making and violence into existing circuits. This changed the balance of power, but European ships did not invent Indian Ocean commerce or the production of spices. Asian, Arab, Persian, African and Indian merchants and ship crews continued to shape the region. The most accurate interpretation is an uneven reorientation: pre-existing networks persisted while European states and chartered companies tried to redirect profits, access and maritime force. [6,23,33]

4. Sahara: salt, gold, caravans and the Sahel

The desert as corridor and ecological challenge

The Sahara is not merely a barrier. It contains oases, wells, salt deposits, grazing zones and market settlements that connect the Mediterranean littoral with the Sahel and western/central Africa. Long-distance movement depended on knowledge of water and routes, animal management, caravan organisation and reciprocal arrangements with local communities. Camel transport made some routes more viable, but did not erase danger, seasonal constraints or regional variation. [11,12,20]

Salt was a staple, not a footnote

Salt from sources such as Taghaza and Bilma moved toward regions where it was scarce and valuable for human and animal diets and for food preservation. It could be exchanged for gold, grain, livestock, textiles and other goods, but the popular image of every salt slab being traded one-for-one for gold is too neat. The Sahara’s regional salt exchanges could exceed the long-distance luxury trade in bulk and economic importance. Salt was essential to ordinary life, while gold was especially visible in accounts of royal wealth. [11,12]

Gold, states and fiscal power

Goldfields in West Africa fed regional and trans-Saharan networks. The Ghana and Mali polities benefited from their position in trade and from relationships with gold-producing zones, while rulers taxed commerce, controlled key centres and sponsored or governed market towns. Mali’s wealth and Mansa Musa’s famous pilgrimage are intelligible only when gold production, Islamic scholarship, caravan logistics, state power and urban commerce are considered together. Yet it would be wrong to claim that merchants or rulers simply ‘owned’ all gold production; extraction and exchange depended on communities and intermediaries beyond the court. [8,11,12]

Ibn Battuta and the limits of a travel account

Ibn Battuta’s account of his 1352-1353 journey across the Sahara records a caravan leaving Sijilmasa, reaching the salt settlement of Taghaza, and depending on imported dates, meat and grain. His description of enslaved workers at the salt mines is a direct reminder that the infrastructure of trade was itself built through labour. But a travel narrative is one situated witness: it reveals what the author saw and chose to record, not a complete statistical description of all Saharan trade or slavery. [20]

Islam, scholarship and the Sahelian city

Islam spread through multiple channels: merchants, rulers, scholars, Sufi networks, migration and the transregional prestige of pilgrimage and Arabic literacy. Shared religion could support trust between some traders and courts, and Timbuktu, Gao, Jenne and other centres became significant commercial and intellectual hubs. Conversion was not instantaneous or uniform; local political arrangements, existing beliefs, social interests and scholarly institutions shaped how Islam was adopted. [8,12,32]

5. Silk Roads: an inland web of intermediaries

Why a chain of exchanges is more plausible than one continuous caravan

The overland Silk Roads crossed steppe, desert, mountain passes, irrigated oases, imperial frontiers and city markets. High-value goods were practical long-distance cargoes because their value justified transport and security costs. A silk textile or bolt could pass through many merchants; each transfer required translation, price information, credit and a changing political environment. UNESCO describes a network of land and maritime paths linking East Asia, Central Asia, South Asia, West Asia and the Mediterranean. [1,2]

Silk, Sogdians and cosmopolitan centres

Silk production originated in China, where sericulture was for a long time a protected skill; it spread over centuries to other regions, reaching Central Asia and the Byzantine world and later parts of Europe. Silk moved as clothing, luxury, diplomatic gift, fiscal resource and a form of wealth. It was not the only important product: textiles, horses, metals, medicines, spices, glass, ceramics and enslaved people also appear in records. [21,2]

Sogdian merchants were especially influential across the inland network during the sixth to eighth centuries. Documents from Turfan list varied goods including silk, horses, metals, medicine, fragrance and enslaved people, pointing to sophisticated commercial communities rather than anonymous caravans. Their networks stretched across Central Asia to China, Persia, India and further west. The political fragmentation after the An Lushan Rebellion reshaped the relative place of inland and maritime commerce; network changes often followed shifts in political security and state control, not a single decisive event. [19]

Religious plurality along the road

The Silk Roads carried Buddhist monks and texts from South Asia through Central Asia into China; they also hosted Zoroastrianism, Manichaeism, forms of Christianity including the Church of the East, Judaism and Islam. Religious buildings and inscriptions attest to overlapping communities in Central Asian towns. Such diversity does not imply modern-style religious equality: communities could coexist, compete for patrons, gain or lose privileges and disappear from a region after political shifts. [2,32]

Technology and knowledge

Paper and papermaking, printing, gunpowder, porcelain, compass knowledge, textile techniques, medical ideas and agricultural practices spread through complex processes across Eurasia. It is more accurate to speak of transmission, adaptation and successive re-engineering than to imagine an intact package carried along a single route. Knowledge could move through artisans, captives, diplomats, soldiers, merchants, monks and state-sponsored workshops; some exchanges happened through maritime routes as well as overland ones. Dates vary by technique and place, and the first surviving evidence in a region is not necessarily the date of first use. [2,31]

6. Atlantic world: forced migration, plantations and imperial commerce

A new oceanic configuration after 1492

The Atlantic after 1492 connected the Americas, Africa and Europe through conquest, settler colonialism, mining, plantation agriculture, forced migration, transoceanic shipping and new flows of crops, animals, pathogens and knowledge. It intersected with older African, Mediterranean and Indian Ocean networks; it did not begin world trade from nothing. What changed profoundly was the Atlantic basin’s integration through European imperial claims and the scale of coerced labour used to produce commodities for distant markets. [16-18,26-29]

Sugar as a system, not simply a sweetener

Sugar illustrates how a commodity can organise land, labour, finance, technology and violence. Sugar plantation production developed in Mediterranean and Atlantic islands before being transferred and expanded in Brazil and the Caribbean. Cane cultivation required intensive work at planting and harvest, while mills and boiling houses required coordination and significant capital. The trade in enslaved Africans, shipping, credit and insurance helped sustain plantation economies; the products then entered European and Atlantic consumer markets. [26,27]

The scale of the Middle Passage

The Trans-Atlantic Slave Trade Database estimates that about 12.5 million Africans were embarked for forced transportation across the Atlantic and about 10.7 million survived to disembark in the Americas. These are reconstructed estimates from documented voyages and statistical inference, not a complete count of every person. The gap between embarkation and arrival represents millions of deaths at sea; it does not capture all deaths during capture, forced marches, coastal detention or after arrival. The database’s estimates are vital precisely because historical ship records are incomplete and distributed across many archives. [15,16]

Commodity chains and imperial power

American silver and gold moved to Europe and, across the Pacific, toward Asian markets; the Manila galleon exchanged New World silver for Chinese silk, porcelain and other Asian goods. Sugar, tobacco, indigo, coffee and later cotton linked plantation zones to merchants, processors, insurers and consumers. The Atlantic triangle is a teaching diagram, not a universal itinerary: individual voyages could run along different routes, and many voyages did not complete a tidy Europe-Africa-Americas-Europe circuit. Insurance, maritime law, state charters and public finance reduced some commercial risks while normalising the treatment of captive people as insured property. [15,18,27-29,41]

The Columbian Exchange was asymmetric

Crops and animals crossed the Atlantic in both directions. Maize, potatoes, cassava, tomatoes, cacao and various beans spread from the Americas to other continents; wheat, rice, sugar cane, cattle, horses and Old World disease environments were introduced to the Americas. Some American crops eventually supported population growth and changed diets in Afro-Eurasia, but adoption took time and depended on ecology, cooking practices, agrarian systems and political decisions. In the Americas, epidemic disease contributed to catastrophic Indigenous population loss alongside warfare, forced labour, dispossession, famine and social

collapse. The scale and timing varied substantially by region, so one universal percentage or single-cause account is unreliable. [17,18,26]

7. Following commodities across regions

This section follows each requested commodity as an analytical thread. The commodity histories do not all share the same geography or chronology: some were truly long-distance goods, while others mattered mostly at regional scales. That difference is itself historically important.

Gold: wealth, taxation and political concentration

Gold moved through several distinct systems: West African production feeding Sahelian and trans-Saharan markets; gold from southern Africa entering western Indian Ocean networks through Swahili ports; Eurasian bullion circulating through state treasuries and commercial settlements; and, after European conquest, American bullion reshaping European and Asian monetary exchanges. Gold had high value relative to weight, making it well suited to long-distance trade and fiscal storage. But gold did not simply ‘create’ states: rulers also required agricultural surpluses, military organisation, legitimacy, bureaucratic capacity and local alliances. Different gold flows should not be collapsed into one continuous chain. [8,12,24,34,41]

Salt: an essential mineral and regional connector

Saharan salt shows how necessity drives trade. It was heavy and relatively low-value by weight compared with gold, so its profitable transport depended on route knowledge, caravan organisation and demand at specific markets. Salt was exchanged for food, livestock, cloth and other items; the exchange could underpin regional specialisation rather than a direct universal gold-salt barter. Stories of gold weighed against salt are evocative but should not substitute for economic history of volumes, labour, prices and seasonal logistics. [11,12,20]

Silk: luxury, diplomacy and technological migration

Silk was prized because of its texture, dyeing potential, status associations and production skill. It moved as fabric, thread, finished garments, diplomatic gifts and taxable wealth. Its production technology gradually moved beyond China, while demand encouraged production in other regions. An item could be labelled ‘Chinese silk’ long after it was woven, dyed or sold elsewhere; historians must distinguish fibre origin, weaving site and last place of trade. [1,21]

Spices: a global appetite with very local origins

Black pepper’s ancient western export chain began in South India and involved upland collectors and coastal intermediaries. Cinnamon and other aromatics came from different ecological regions; cloves and nutmeg were associated with islands in eastern Indonesia. ‘Spices from the East’ therefore concealed multiple growing regions, social arrangements and bottlenecks. European competition after 1500 sought not only to buy spices but also to control production zones and sea lanes, raising the importance of forts, monopoly rights and coercive commerce. [4,23]

Grain: subsistence, shipping and state legitimacy

Grain generally travelled in lower-value bulk than silk and pepper, making transport costs and state organisation central. Rome’s annona system depended on public grain flows from provinces including Sicily, Sardinia, Africa and Egypt; Egypt’s tax grain later became important to Constantinople. These flows tied

agriculture, tax collection, shipping contracts, port administration and urban provisioning to imperial stability. Grain also moved within Indian Ocean and Southeast Asian networks: studies of eastern India show substantial movement from surplus to deficit areas. The trade in foodstuffs could affect survival and political legitimacy even when it did not create the same spectacular wealth as gold or spice. [13,14,22]

Enslaved labour: compare institutions, do not flatten them

The forced movement of people connected all four broad worlds, but there was no single global system called ‘slavery’ with one legal form or labour regime. Enslaved persons were used as domestic workers, agricultural labourers, miners, soldiers, porters, sailors, concubines and court dependants in different times and places. Some systems offered possibilities of manumission or incorporation; others hardened hereditary status. These variations do not make enslavement benign: they make the historical analysis more exact. [15,25-29]

8. Disease and demographic shock

A connected route is a possible transmission pathway, not proof of cause

People, animals, fleas, cargo, water, food, ships and settlement patterns formed ecological networks. But the evidence needed to reconstruct disease movement differs by pathogen. Written chronicles can describe epidemic waves but misidentify causes; archaeological burials can locate mortality clusters but not always identify infection; ancient DNA can identify pathogens but does not automatically reconstruct every transmission step. Claims should therefore be ranked by evidence rather than fitted to a convenient map of trade routes. [30,35]

The Black Death and Central Asia

A 2022 Nature study analysed ancient DNA from individuals buried at Kara-Djigach and Burana in the Chüy Valley, in present-day Kyrgyzstan. Tombstone inscriptions dated to 1338-1339 referred to a ‘pestilence’; reconstructed Yersinia pestis genomes from seven individuals represented a strain identified as the most recent common ancestor of a major diversification associated with the second plague pandemic. This materially strengthens the link between a Central Asian outbreak and the ancestry of Black Death-associated plague, but it does not mean that every later epidemic spread via one simple ‘Silk Road route’. The movement into the Black Sea, Mediterranean and Europe involved a changing landscape of political control, caravan links, ports, ships, rodent hosts and human mobility. [30]

The Columbian Exchange and Indigenous America

After 1492, the arrival of Old World pathogens in the Americas was one part of a dramatic demographic catastrophe. Some Indigenous communities had no previous exposure to particular infections, but susceptibility, mortality and epidemic sequence differed across regions. Disease interacted with conquest, warfare, forced labour, food shortages, displacement, disrupted care, and the reorganisation of settlement. The reverse movement of crops and diseases also occurred, but the demographic imbalance was profound. It is misleading to treat the whole process as a natural event without human responsibility, or to attribute every population decline to pathogens alone. [17,18]

Disease in maritime worlds

Ports and ships concentrated people and goods; long waiting periods and crowded urban environments could amplify infection. Malaria and smallpox affected patterns of labour demand and mortality in the western Indian Ocean, but illness also shaped the profitability and organisation of slavery by raising the death risks faced by captives and workers. Disease did not act as an external force separate from commerce: labour regimes, housing, diet, movement, violence and health environments shaped who was exposed and who could recover. [25,27,35]

9. Technologies, knowledge and infrastructure

Movement depends on systems, not inventions alone

A technology becomes historically consequential when it is embedded in skills, materials, maintenance, training, institutions and demand. A compass without charting practice and maritime experience is not enough; a camel without fodder, wells and route knowledge is not a caravan system; a sugar mill without capital, cane fields, skilled operators and coerced labour is not a plantation complex. Technology transfer therefore has social history.

Technology / practice Role in connected-world history What to avoid claiming

Transfer is rarely a one-step story

When a technology appears in a new region, several processes may have contributed: migration of craftspeople, transfer through prisoners of war, diplomatic gift exchange, merchant demonstration, imitation of imported objects, military competition, state-directed projects or independent development. Written testimony may identify one route but omit others; archaeological remains may show that an object was present but not how its maker learned the process. Technology should be studied as a history of people and institutions, not as a scoreboard of civilisational superiority. [2,19,31]

10. Religious ideas and cultural translation

Faith travelled with people, institutions and practice

Religions moved through several channels. Buddhist monks, merchants and translators carried texts and images from South Asia through Central Asia toward China and East Asia. Zoroastrian, Manichaean and Christian communities formed around settlements and court patronage along the Silk Roads. Islam spread through North African and West Asian commercial and scholarly networks and across the Sahara; in the Indian Ocean, merchants and rulers helped Islam take root in port cities and Southeast Asian polities. Hindu traditions and Buddhist practices also travelled by sea into Southeast Asia. These processes were multi- generational and locally mediated. [2,8,10,32]

Commerce may support trust without explaining belief

Shared legal language, ritual calendars, reputations and institutions can make exchange easier among some groups. Yet trade alone does not explain why people converted. Rulers could adopt a religion for legitimacy or

diplomacy; individuals and communities could be drawn by ritual practice, ethical teaching, education, marriage, patronage, Sufi networks or local reinterpretations. Merchants might trade across religious boundaries while maintaining their own traditions. The causal relation is reciprocal but not automatic: commerce can create contact; contact can facilitate ideas; institutions and local choices shape the result. [3,8,10]

Atlantic religion and diaspora

The Atlantic world carried Christianity through missionary institutions, colonial states and settler societies, while enslaved Africans carried diverse religious knowledge, cosmologies, music, healing practices and ritual forms across the ocean. Some survived openly, some were adapted through syncretism, and some were sustained under repression or in maroon communities. Enslaved people’s religious lives were not simply passive outcomes of conversion policies; they were part of cultural survival, resistance and creativity. The same movement of people that generated forced displacement also created durable diasporic cultures. [17,26,28]

Ideas also travelled against the grain of power

Merchants, migrants and scholars could carry criticism of rulers, unfamiliar legal practice, new ethical concepts and alternative accounts of the world. Religious networks might legitimise states, but they could also furnish universal moral vocabularies that challenged rulers, slavery or injustice. Historical analysis should not assume that any religion always served power or always resisted it; the relationship changed by institution, place and political moment.

11. Labour, power, credit and unequal gains

Who captured the margin?

A trade flow does not tell us who received its gains. Prices were shaped by transport risk, local monopsony or monopoly, taxes, credit, access to labour, bargaining power and the ability to enforce a contract. A court could earn customs duties without producing the commodity; a port broker could make money by knowing local conditions; a merchant could protect a shipment through insurance; a plantation owner could increase output by violence against captive workers. Producers, carriers, tax collectors and final sellers occupied different positions within one chain.

States rarely stood outside commerce

States protected, taxed, monopolised, subsidised or redirected trade. Roman public grain provisioning tied provincial taxes to urban order. Mali’s political authority was connected with key trade zones and commercial centres. Silk Road empires invested in posts and controlled passes. Atlantic empires granted charters, claimed territories, enforced racialised legal codes and supported the naval infrastructure of plantation commerce. State power often made exchange possible while also extracting rents and imposing costs. [2,8,13,15,27]

Credit and trust

Long-distance exchange needs finance as much as movement. Loans, letters, brokers, partnerships, reputation, religious or community institutions, and later maritime insurance could spread risk over time and distance. Credit did not eliminate risk: it reassigned risk among borrowers, lenders, shipowners, insurers, merchants, states and labourers. The Atlantic slave trade offers a stark example because commercial

instruments that looked technically neutral also helped make human captivity a predictable and financeable business. [4,19,27,29]

Connectivity and coercion

The connected world is often described in celebratory language: exchange, cosmopolitanism, diffusion, innovation. These are real phenomena, but they are not the whole story. Mobility might be voluntary, strategic, compelled or forced. Merchant diasporas and pilgrims could travel by choice; soldiers, captives, enslaved people and displaced communities frequently did not. Even workers described as free could face debt, state corvée, coercive labour contracts or colonial monopolies. Good global history counts both connection and its unequal terms.

12. Five comparative case studies

Case 1. Muziris and the Indo-Roman pepper chain

Evidence: ancient literary accounts, the Muziris papyrus and archaeological finds such as Roman coins. The case shows how a local commodity became a high-value export within a chain crossing inland ecologies, coastal ports, the Arabian Sea, Red Sea, Egypt and the Mediterranean. It also reveals credit and fiscal structures: the papyrus is valuable because it records a loan associated with a cargo and the legal-financial arrangements surrounding it. Limitation: surviving evidence is unusually rich for some transactions and does not represent every merchant, commodity or coastal community. [4,5,7]

Case 2. Kilwa, Sofala and gold from southern Africa

Evidence: Swahili coast settlements, imported ceramics, coin finds, architecture and written accounts. Coastal city-states linked inland exchange zones to the Indian Ocean; Kilwa’s commercial fortunes were strongly associated with gold arriving through Sofala and linked routes. The case helps correct an Africa-as-isolated- continent model: imported goods reached inland centres such as Great Zimbabwe through multi-stage trade. Limitation: material imports demonstrate exchange and reach but do not prove direct contact between every origin and destination, nor tell us the exact volume of trade. [8,24]

Case 3. Taghaza and the human infrastructure of salt

Evidence: Ibn Battuta’s fourteenth-century narrative and wider histories of Saharan market towns. The salt-mining settlement depended on imports from outside the desert and on labourers extracting and carrying salt in difficult conditions. It makes visible the two-way dependence of caravan systems: mineral resources from one ecological zone were paid for with food and goods from another, while workers bore harsh costs. Limitation: one travel account is a snapshot, not a quantitative survey of all Sahara routes. [11,12,20]

Case 4. Chüy Valley, 1338-1339 and the Black Death

Evidence: tombstone inscriptions referring to pestilence and ancient DNA from seven individuals. The case shows how inscriptions, archaeology and genetics can illuminate a disease event that written chronicles alone could not securely locate. The genomes point to a key ancestral lineage of plague associated with the second pandemic. Limitation: identifying a lineage does not map all later transmission events, the balance of routes or the role of each vector. [30]

Case 5. Atlantic sugar, credit and slavery

Evidence: shipping records, plantation records, voyage databases, insurance documents and colonial laws. The case joins commodity production to forced migration, technical processing, finance and state violence. SlaveVoyages estimates approximately 12.5 million embarkations and 10.7 million arrivals, illuminating a scale that no single national archive could reconstruct. Limitation: databases are only as complete as their records, estimates can change as archives are added, and voyage counts cannot by themselves capture all deaths and suffering outside the ship. [15-18,26-29]

13. What the evidence can and cannot show

How confidence is handled in this report

• High confidence: there is converging textual, material or genomic evidence, and the claim is narrow enough to be directly supported.
• Moderate confidence: the general pattern is widely supported, but exact quantities, chronology or mechanisms remain incomplete.
• Low confidence / contested: the underlying record is sparse, geographically biased or hard to compare; no exact number or single causal route should be asserted. Historical knowledge improves when sources are compared rather than ranked by glamour. A customs document may reveal a tax on a cargo; a coin may establish circulation; a landscape may reveal the need for irrigation; a burial may preserve a pathogen. None is enough alone to reconstruct a complete commercial world.

14. Conclusion: connected, not uniform

Across the Indian Ocean, Sahara, Silk Roads and Atlantic, the most important story is not merely that distant goods travelled. These networks linked ecological zones and specialised economies; connected port cities, caravan towns, states and diasporas; moved knowledge and religious practice; and shaped the distribution of wealth, risk and coercion. Gold and silk help make the story visible, but salt, grain, textiles, food crops, credit and human labour explain how it worked.

The Indian Ocean highlights seasonal maritime knowledge and locally rooted port networks. The Sahara shows how ecological constraint and caravan organisation linked the Sahel to North Africa and beyond. The Silk Roads reveal the power of intermediaries, oasis towns and shifting imperial security. The Atlantic system joined transoceanic exchange to conquest and a large plantation complex that depended on racialised hereditary slavery. All four were capable of carrying disease, technologies and religious ideas, but the routes and outcomes were never identical.

The central analytical warning is that connection should not be mistaken for equality, integration or progress. Trade could transmit ideas and improve access to goods; it could also finance war, extract resources, displace communities and commodify people. The same network may have generated profit for one actor and death or dispossession for another. A rigorous connected-world history therefore asks five questions every time: What moved? Who moved it? What institutions made movement possible? Who benefited? Who bore the cost?

Final assessment: premodern Afro-Eurasian trade networks were extensive and regionally sophisticated before Atlantic expansion. After 1492, Atlantic conquest, plantation slavery, bullion flows and the Columbian Exchange reorganised the balance of global connectivity, without erasing older networks or their local actors.

Appendix A. Comparative matrix

Appendix B. Selected chronology

Appendix C. Glossary

Selected bibliography and digital sources

The references below prioritise academic publishers, UNESCO, research databases, and scholarly overview sources. URLs were checked during preparation; access to some book chapters may require institutional access. Numbering is aligned to in-text citations. [1] UNESCO. “About the Silk Roads.” Silk Roads Programme. https://www.unesco.org/en/silk-roads/about-silk-roads?hub=196704 [2] UNESCO World Heritage Centre. “Silk Roads: The Routes Network of Chang’an-Tianshan Corridor.” https://whc.unesco.org/en/list/1442/ [3] “Networks and social cohesion in ancient Indian Ocean trade: geography, ethnicity, religion.” Journal of Global History, Cambridge University Press (2013). https://www.cambridge.org/core/journals/journal-of-global-history/article/networks-and- social-cohesion-in-ancient-indian-ocean-trade-geography-ethnicity-religion/D32B1FF1DCA90833C02C80E7B37B166E [4] De Romanis, Federico. The Indo-Roman Pepper Trade and the Muziris Papyrus. Oxford University Press, 2020. https://academic.oup.com/book/40562 [5] Copeland, Conrad. “Riding the monsoon: Geography and Iron Age trade in the Indian Ocean.” Economic History Review (first published 22 April 2025). https://onlinelibrary.wiley.com/doi/10.1111/ehr.70016 [6] Abu-Lughod, Janet L. Before European Hegemony: The World System A.D. 1250-1350. Oxford University Press, 1991. https://academic.oup.com/book/54378

[7] “The Archaeological Record of Indian Ocean Engagements: Bay of Bengal (5000 BC-500 AD).” Oxford Handbook of Topics in Archaeology. https://academic.oup.com/edited-volume/43506/chapter/364133129 [8] OpenStax. “The Roots of African Trade.” World History, Volume 2: From 1400. https://openstax.org/books/world-history- volume-2/pages/3-1-the-roots-of-african-trade [9] OpenStax. “North Africa’s Mediterranean and Trans-Saharan Connections.” World History, Volume 1: To 1500. https://openstax.org/books/world-history-volume-1/pages/9-4-north-africas-mediterranean-and-trans-saharan-connections [10] Oxford Research Encyclopedia of Asian History. “Commercial Networks Connecting Southeast Asia with the Indian Ocean.” https://academic.oup.com/edited-volume/61799/chapter-abstract/546286170 [11] Oxford Handbook Topics in History. “Crossroads Regions: The Sahara.” https://academic.oup.com/edited-volume/41326/chapter/352325481 [12] Nixon, Sam. “The Early Islamic Trans-Saharan Market Towns of West Africa.” In Urbanisation and State Formation in the Ancient Sahara and Beyond. Cambridge University Press, 2020. https://www.cambridge.org/core/books/abs/urbanisation- and-state-formation-in-the-ancient-sahara-and-beyond/early-islamic-transsaharan-market-towns-of-west-africa/ F6D1A9A38BA504DB817D1D365D3572A1 [13] Oxford Classical Dictionary. “Annona (grain).” Oxford University Press. https://academic.oup.com/edited-volume/61673/chapter-abstract/548063756 [14] “People, Plagues, and Prices in the Roman World: The Evidence from Egypt.” Journal of Economic History, Cambridge University Press. https://www.cambridge.org/core/journals/journal-of-economic-history/article/people-plagues-and-prices-in-the- roman-world-the-evidence-from-egypt/50D27EAD5045D12C1573DFFB5D5C029C [15] SlaveVoyages. The Trans-Atlantic Slave Trade Database: Methodology and estimates. https://legacy.slavevoyages.org/blog/methodology-trans-atlantic [16] National Endowment for the Humanities. “The Transatlantic Slave Trade Database.” https://www.neh.gov/project/transatlantic-slave-trade-database [17] Nunn, Nathan, and Nancy Qian. “The Columbian Exchange: A History of Disease, Food, and Ideas.” Journal of Economic Perspectives 24, no. 2 (2010): 163-188. https://pubs.aeaweb.org/doi/10.1257/jep.24.2.163 [18] OpenStax. “New Worlds in the Americas: Labor, Commerce, and the Columbian Exchange.” U.S. History. https://openstax.org/books/us-history/pages/2-4-new-worlds-in-the-americas-labor-commerce-and-the-columbian-exchange [19] Oxford Research Encyclopedia of Asian History. “The Sogdian Merchant Network.” Oxford University Press. https://academic.oup.com/edited-volume/61799/chapter-abstract/546314742 [20] Ibn Battuta. “Ibn Battuta prepares to cross the Sahara” (1352), translated excerpt, Internet History Sourcebooks Project, Fordham University. https://sourcebooks.web.fordham.edu/source/1354-ibnbattuta.asp [21] The Metropolitan Museum of Art. “Silk,” Exhibition Themes, Animal Fibers. https://www.metmuseum.org/exhibitions/listings/2016/animal-fibers/exhibition-themes [22] Arasaratnam, S. “The Rice Trade in Eastern India 1650-1740.” Modern Asian Studies, Cambridge University Press. https://www.cambridge.org/core/journals/modern-asian-studies/article/abs/rice-trade-in-eastern- india-16501740/71E6916E3130B072BC6FBCDF5B65D915 [23] Royal Museums Greenwich. “The Spice Islands.” https://www.rmg.co.uk/stories/maritime-history/spice-islands [24] OpenStax. “East-West Interactions in the Early Middle Ages.” World History, Volume 1: To 1500. https://openstax.org/books/world-history-volume-1/pages/12-2-east-west-interactions-in-the-early-middle-ages [25] Allen, Richard B. “Africans in the Indian Ocean World.” Oxford Research Encyclopedia of African History (2020). https://academic.oup.com/edited-volume/61663/chapter-abstract/553416714 [26] Davis, David Brion. “The Atlantic Slave System: Brazil and the Caribbean.” In Inhuman Bondage: The Rise and Fall of Slavery in the New World. Oxford University Press, 2006. https://academic.oup.com/book/47608/chapter-abstract/422640257 [27] Pearson, Robin, and David Richardson. “Insuring the Transatlantic Slave Trade.” Journal of Economic History (2019). https://doi.org/10.1017/s0022050719000068 [28] Encyclopedia Virginia. “The Transatlantic Slave Trade and the Middle Passage.” https://encyclopediavirginia.org/entries/transatlantic-slave-trade-the/ [29] Encyclopedia Virginia. “The Economy of the Enslaved in Virginia.” https://encyclopediavirginia.org/entries/the-economy- of-the-enslaved-in-virginia/

[30] Spyrou, Maria A., et al. “The source of the Black Death in fourteenth-century central Eurasia.” Nature 606 (2022): 718-

724. https://www.nature.com/articles/s41586-022-04800-3 [31] UNESCO World Heritage Centre. “Silk Road Sites in Uzbekistan.” Tentative List description of technology and knowledge circulation. https://whc.unesco.org/en/tentativelists/5500/ [32] UNESCO. “About the Silk Roads.” Sections on religions, arts, science and cultural exchange. https://www.unesco.org/en/silk-roads/about-silk-roads?hub=196704 [33] Oxford Research Encyclopedia of Asian History. “Commercial Networks Connecting Southeast Asia with the Indian Ocean.” https://academic.oup.com/edited-volume/61799/chapter-abstract/546286170 [34] Oxford Research Encyclopedia of African History. “African Economic History and Historiography.” https://academic.oup.com/edited-volume/61663/chapter/553498316 [35] Spyrou, Maria A., et al. (2022), as above; see also the accompanying Nature research briefing, “Ancient DNA traces origin of Black Death.” https://www.nature.com/articles/d41586-022-01673-4 [36] Cambridge University Press. “Slavery and the Slave Trade in the Western Indian Ocean World.” In The Cambridge World History of Slavery, 2021. https://www.cambridge.org/core/books/cambridge-world-history-of-slavery/slavery-and-the-slave- trade-in-the-western-indian-ocean-world/238C56DA8DC84C6AA51E4A0D6F9E5F33 [37] Wint, Hollian. “Financing the Indian Ocean Slave Trade.” Oxford Research Encyclopedia of African History (2022). https://academic.oup.com/edited-volume/61663/chapter-abstract/553387533 [38] UNESCO. The Silk Roads: A Brief History with Documents, edited by Xinru Liu. Silk Roads Programme. https://en.unesco.org/silkroad/publications/silk-roads-brief-history-documents [39] Oxford Research Encyclopedia of Asian History. “The Sogdian Merchant Network.” https://academic.oup.com/edited- volume/61799/chapter-abstract/546314742 [40] Oxford Academic. Abu-Lughod, Before European Hegemony: “The Indian Subcontinent: On the Way to Everywhere.” https://academic.oup.com/book/54378/chapter-abstract/422517636 [41] Hecht, Johanna. “The Manila Galleon Trade (1565-1815).” The Metropolitan Museum of Art, Heilbrunn Timeline of Art History (2003). https://www.metmuseum.org/de/essays/the-manila-galleon-trade-1565-1815

Research note

This report is a comparative synthesis, not an exhaustive archival catalogue. It relies on published scholarship and curated institutional sources. Several references are duplicated intentionally where one work supports distinct strands of the analysis. Numerical ranges, particularly estimates of forced migration, are presented as estimates. Claims about disease, trade volume and technology transfer are restricted to what the cited evidence can reasonably establish.