 The Battle of Orbetello , also known as the Battle of Isola del Giglio , was a major naval engagement of the Franco @-@ Spanish War of 1635 . It was fought on 14 June 1646 off the Spanish @-@ ruled town of Orbetello , on the coast of Tuscany , Italy , between a French fleet led by Admiral Armand de Maillé , and a Spanish fleet led by Admiral Don Juan de Mena . The battle was the first major naval engagement of the war, and it marked the first time that the Spanish @-@ had been defeated at sea by the French @-@ in a major battle at sea since the Battle of Lepanto in