Chapter 5 sets the stage for the rest of the story. While several infectious agents were exported from Africa to the Americas and the Caribbean during the slave trade, this was not the case with HIV, which indirectly confirms its relatively recent emergence in central African populations. This chapter briefly tells the story of the European colonisation of central Africa by France and Belgium. It explains how the Franco-Belgian incursion in south-east Cameroon during World War I (1914–16) created much greater intermingling of populations and may have provided a route for HIV to reach the Stanley Pool.