When Elisabeth Farnese became Philip's second wife in 1714, he already had two sons who were next in line for the Spanish throne. She wanted to create an Italian inheritance for her own children, while Philip viewed regaining these territories as important for his prestige. Spain re-occupied Sardinia unopposed in 1717 but a landing on Sicily in 1718 led to the War of the Quadruple Alliance. The Royal Navy's victory at Cape Passaro in August isolated the Spanish invasion force and ultimately forced them to surrender to Austrian troops in 1719.