The failure of the Pazzi Conspiracy against Florence in 1480 and unexpected peace as a result of Lorenzo de' Medici's daring personal diplomacy with Ferdinand I of Naples, the Pope's erstwhile champion, was a source of discontent among the Venetians and Pope Sixtus IV alike. Venice had ended its long conflict with the Ottoman Turks in 1479, with the Treaty of Constantinople, and was freed to turn its complete attention to its role in its terra firma (main land) and generally to the peninsula of Italy.