Joao De Castro, a Portuguese naval hero and explorer, born in Lisbon in February, 1500, died in Goa, June 6, 1548. He belonged to an ancient family, and early became proficient in mathematics, having as teacher Pedro Nunez, and as fellow student the infante Dom Luis. He accompanied the latter in the expedition to Tunis in 1533, after having been previously knighted by the governor of Tangier; a similar honor was offered to him at Tunis by Charles V., but declined. In 1538 he was made commander of a small religious order, and soon afterward went with his uncle to Goa, where lie served against the Moors. In 1540 he explored the Red sea under Estevao da Gama; in 1543 he was placed in command of a naval expedition for the extirpation of piracy; and in 1545 he was appointed councillor of the crown and governor of Goa. In 1546 he gained a celebrated victory over the Moors at Diu, and was celebrated by Camoens as Castro forte (the powerful Castro). The king of Portugal, though never partial to him, appointed him viceroy of India, Oct. 13,1547. He died soon afterward in the arms of St. Francis Xavier, and a statue was erected in his honor at Goa. His remains were removed in 1576 to Portugal, and deposited with great pomp in the convent of Bemfica. His MS. log book (Roteiro) of his hydrographical investigations in the Red sea, preserved in the British museum, was first published in Paris in 1833, and possesses great scientific merit.

He left also MS. narratives of his voyage from Lisbon to Goa, and from Goa to Diu. His biography was published in Lisbon in 1651, by Jacintho Freyre de Andrada.