The Bastard Don John of Austria.

Don Juan de Austria (1547 - 1578), in English known as Don John of Austria, was a prominent contemporary of Lope de Vega in Madrid. He was an illegitimate son of Holy Roman Emperor Charles V, and was thus the half-brother and rival of King Philip II of Spain and brother in law to his wife, Queen Mary Tudor. He became a military leader in the service of King Philip and is best known for his naval victory at the Battle of Lepanto in 1571 against the Ottoman Empire, while based in Messina (as shown in Much Ado). See Emrys Jones "Othello, Lepanto, and the Cyprus Wars," Shakespeare Survey 21 (1968), 47-52. King James I wrote a poem called "Lepanto," published in 1591, and noted by many Elizabethan authors. Don John also proposed an Armada to reconquer England for Catholicism and so was much feared and hated there. Both Shakespeare and Calderon put him on stage. Detail from "The Victors of Lepanto" by an unknown artist, 1575, in the Kunsthistorisches Museum, Vienna. Picture and data courtesy of the Yorck Project, under Creative Commons Attribution-Share- Alike License (Wikipedia).