Trade and Geography in the Spread of Islam

Abstract

In this study we explore the historical determinants of contemporary Muslim representation. Motivated by a plethora of case studies and historical accounts among Islamicists stressing the role of trade for the adoption of Islam, we construct detailed data on pre-Islamic trade routes, harbors, and ports to determine the empirical regularity of this argument. Our analysis - conducted across countries and across ethnic groups within countries - establishes that proximity to the pre-600 CE trade network is a robust predictor of today's Muslim adherence in the Old World. We also show that Islam spread successfully in regions that are ecologically similar to the birthplace of the religion, the Arabian Peninsula. Namely, territories characterized by a large share of arid and semiarid regions dotted with few pockets of fertile land are more likely to host Muslim communities. We discuss the various mechanisms that may give rise to the observed pattern.

Keywords: Geographic Inequality; Geography; Islam; Religion; Trade Routes.

Figure 1 –. Muslim Adherence and Ancient Trade Routes – Selected Countries

Figure 1 portrays Muslim adherence at the ethnic group level and historical trade routes within five countries (1a: China, 1b: Mali, 1c: Tanzania, 1d: Indonesia and 1e: India). Muslim adherence is represented in quintiles at the level of ethnic group, where actual homelands are from the Ethnologue version 15 and data on religious affiliation from the World Religion Database. Darker shades represent higher Muslim shares in the population. In Figures 1a, 1c, and 1e the trade routes are depicted as thick, black-and-white dashed lines and correspond to pre-600 CE. These routes are digitized from Brice and Kennedy (2001). The ancient ports and harbors, depicted as circled stars, are from Arthur de Graauw (2014). In figure 1b trade routes are relative to 900 AD, while in figures 1c and 1d ports in year 600 CE (1800 CE) are represented with circled stars (circled dots). Country borders are represented with a thin dashed grey line.

Figure 1 –. Muslim Adherence and Ancient Trade Routes – Selected Countries

Figure 1 portrays Muslim adherence at the ethnic group level and historical trade routes within five countries (1a: China, 1b: Mali, 1c: Tanzania, 1d: Indonesia and 1e: India). Muslim adherence is represented in quintiles at the level of ethnic group, where actual homelands are from the Ethnologue version 15 and data on religious affiliation from the World Religion Database. Darker shades represent higher Muslim shares in the population. In Figures 1a, 1c, and 1e the trade routes are depicted as thick, black-and-white dashed lines and correspond to pre-600 CE. These routes are digitized from Brice and Kennedy (2001). The ancient ports and harbors, depicted as circled stars, are from Arthur de Graauw (2014). In figure 1b trade routes are relative to 900 AD, while in figures 1c and 1d ports in year 600 CE (1800 CE) are represented with circled stars (circled dots). Country borders are represented with a thin dashed grey line.

Figure 2 –. Main Old World trade routes

Figure 2a (2b) shows the Old World network of Roman roads (from the Barrington Atlas), ancient ports and harbours (from Arthur de Graauw, 2014) and trade routes (from Brice and Kennedy, 2001) in 600 AD (1800 AD).

Figure 3 –. Non-parametric conditional correlation – Cross-country

Figure 4 –. Non-parametric conditional correlation – Cross-ethnic group