Answer:
Spain joined with Venice and other Italian states in the Battle of Lepanto because of their same religion, Catholicism, which inspired them to fought against the muslim Ottoman Empire for the control of the Mediterranean.
Explanation:
The battle of Lepanto was a naval combat that took place on October 7, 1571 near the Greek city of Nafpaktos.
They faced the Ottoman Empire's army against that of a Catholic coalition, called the Holy League, formed by the Kingdom of Spain, the Papal States, the Republic of Venice, the Order of Malta, the Republic of Genoa and the Duchy of Savoy.
The Catholics, led by John of Austria, were victors, and only thirty Ottoman galleys were saved. The Ottoman expansionism in the eastern Mediterranean was halted for a few decades and the Ottoman allied corsairs were forced to abandon their attacks and expansions to the western Mediterranean.