Catholic hero, born Ratisbon, Bavaria, 1545; died Namur, Belgium, 1578. The natural son of Charles V, by Barbara Blomberg, daughter of an affiuent family, he was recognized later by his half-brother, Philip II, as a member of the royal family. Having distinguished himself in conflicts with the Algerian pirates, 1568, and the Morlscos in Granada, 1569-1570, he was made admiral of the Spanish and Austrian fleets, combined by the league effected by Pope Pius V, 1571, to check the advance of the Turks to the west after their conquest of Cyprus. The great victory of Lepanto, Greece, when 35,000 Turks were slain and 15,000 Christian slaves freed, inspired Don Juan to work for his own and Christianity's establishment in non-Christian countries, but he was thwarted by the jealous Philip, and made governor-general of the Netherlands, 1576, only to encounter the opposition of William of Orange, all-powerful there. Even after signing the "Perpetual Edict," 1577, his position remained nominal, so he withdrew shortly to Namur. Staging the attack, led by Faroese, on Gemblours, 1578, he could not follow up the brilliant victory for lack of funds, and after a period of inactivity, his health failed and he died, broken-hearted.