COSA, Juan de la, Spanish navigator, born in the latter part of the 15th century; died in 1509. He accompanied Columbus, as pilot, in his second voyage. Having become noted for his great ability and vast knowledge as a navigator, he was entrusted with the command of three expeditions to the coasts and territories of Darien, and on returning to Spain was rewarded for his discoveries with special honors and the title of alguacil mayor of those regions explored by him. In 1509 he accompanied Ojeda in another expedition to the same country, and the explorers landed, against his advice, at the place where the City of Cartagena is row. When Ojeda had gone some distance into the country, he and his men were attacked and surrounded by many thousands of Indians. De la Cosa went at once to his aid, fought with astonishing bravery, resisted desperately against the continuous attacks of numberless Indians, and, after three hundred of his companions had perished in the battle, he also fell under the poisoned arrows of the enemy. A few days afterward Ojeda found the body of his heroic friend hanging from a tree.