Sir: Mr Nigel Tattersfield's Historical Notes (16 November) overlook the slave trade in East Africa. Here again, local Africans took part, selling slaves to the Portuguese and Arabs at Zanzibar. Dr Livingstone estimated in the mid-19th century that 50,000 slaves were sold through that market and that, for every slave sold, four had died on the way to the coast. Some 250,000 people were, therefore, being extracted from Uganda, Tanzania and elsewhere. Once sold, they were shipped by dhow up to Saudi Arabia. The Sultan of Muscat had "and Zanzibar" as part of his title.
W R HAINES