>Our key 1500 AD result implies large magnitudes. Regressing income today on the migration-weighted index for 1500 AD, a coefficient of 3.261 implies that a movement from 0 to 1 is associated with an increase in per capita income today by a factor of 26.1. The log difference in per capita income today between Western Europe and sub-Saharan Africa is 2.59 (a factor of 13.3). This income difference is usually attributed to the post-1500 slave trade, colonialism, and post-independence factors in sub-Saharan Africa. The averages for Western Europe and sub-Saharan Africa on the migration-weighted technology index in 1500 AD are 0.923 and 0.303, respectively. The log per capita income difference today associated with that 1500 AD technology difference is 3.261 × (0.923 − 0.303) = 2.023 (a factor of 7.6). Thus, 78 percent of the log difference in income today between subSaharan Africa and Western Europe (2.023/2.59) is associated with the technology differences in 1500 AD.

>https://dcomin.host.dartmouth.edu/Publications_files/1000BC.pdf

Europe was already richer and more advanced than Africa in the late medieval period. Additionally, it's worth mentioning that like today, back in the colonial era, most trade in the world was between rich countries. Right now the USA trades and invests more with Canada (917.4 billion in trade and 683.8 billion in FDI) than all of Africa (71.6 billion in trade and 56.29 billion in FDI).