In 1554 John Lok was captain of three ships, the Trinity of 140 tons, the Bartholomew of 90 tons, and the John Evangelist of 140 tons which set sail on a trading voyage to Guinea on 11 October. Although unfavourable winds kept them from leaving England's shores until 1 November, they were near Madeira by 17 November, and becalmed two days later at the Canary Islands under the Peak of Tenerife. They touched the coast of Africa at Cape Barbas, and after reaching the mouth of the Sestos River, traded down the coast, 'touching every place of consequence without any memorable incident occurring' until 13 February, when they turned back toward England. Although the voyage out had taken seven weeks, the return voyage took twenty. In all, twenty-four seamen were lost in the course of the voyage. The cargo brought back included more than 400 pounds' weight of gold, 36 butts of Guinea pepper, and 250 elephants’ tusks, as well as an elephant's skull of such size and weight that a man could scarcely lift it.^{[17][18][19][20]} Lok's ships also brought home five Africans from present-day Ghana to learn English and act as interpreters on future trading voyages to Guinea. 
There is talk that this is when the slave trade first occurred.