John I of Castile died in 1390 without issue from his wife Beatrice, which meant that a competing legitimate bloodline with a claim to the throne of Portugal died out. John I of Portugal was then able to rule in peace and concentrate on the economic development and territorial expansion of his realm. The most significant military actions were the siege and conquest of the city of Ceuta by Portugal in 1415, and the successful defence of Ceuta from a Moroccan counterattack in 1419. These measure were intended to help seize control of navigation off the African coast and trade routes from the interior of Africa.