João de Castro, Portuguese nobleman and fourth viceroy of Portuguese India (d. 1548)
Dom João de Castro (7 February 1500 – 6 June 1548) was a Portuguese nobleman, scientist, writer, and the fourth viceroy of Portuguese India. He was called Castro Forte ("Stronghold" or "Strong Castle") by the poet Luís de Camões. De Castro was the second son of Álvaro de Castro, the civil governor of Lisbon. His wife was Leonor de Coutinho.