 They were the most knowledgeable in the maritime navigation of Guinea so Valera returned to Andalusia.This expedition obtained few economic benefits, as most of the slaves were returned to the Marquis of Cadiz, and Valera was forced to indemnify the Duke of Medina Sidonia for the damages caused on the Island of Noli, which the Duke claimed as his.On September 23, 1475, Louis XI of France signed a treaty of alliance with Afonso V of Portugal.