In the 1600s, European travellers noticed that East African folks smoked it working with coconut-based drinking water pipes (Comoros) and antler-dependent pipes in Madagascar. A Portuguese account from the 1580s reviews the usage of ‘bangue’ in the region, that is thought to relate into the area expression for cannabis – https://dallasgcwqj.wikibriefing.com/3678037/zanzibar_cannabis_an_overview