The
Holy League (, ) of 1571 was arranged by Pope
St. Pius V and included almost all the major
Catholic maritime states in the
Mediterranean. It was intended to break the
Ottoman Turks' control of the eastern Mediterranean Sea and was formally concluded on 25 May 1571. Its members were the
Papal States, the
Habsburg states of
Spain,
Naples and
Sicily, the
Republic of Venice, the
Republic of Genoa, the
Grand Duchy of Tuscany, the Duchies of
Savoy,
Parma and
Urbino and the
Knights of Malta. These states were to have a force of 200
galleys, 100 other ships, 50,000 infantry, 4,500 cavalry and adequate artillery ready by 1 April each year.
Don Juan de Austria, illegitimate half-brother of King
Philip II of Spain, was designated supreme commander. The League kept membership open for the
Holy Roman Empire,
France and
Portugal, but none of them joined. The Empire preferred to maintain its truce with Istanbul, while France had an active anti-Spanish alliance with the Ottomans. Portugal was heavily engaged in its own
Moroccan campaign and its ongoing maritime confrontations with the Ottomans in the
Red Sea and the
Indian Ocean and had no forces to spare.