The Spanish conquest of Sardinia, also known as the Spanish expedition to Sardinia, took place between the months of August and November 1717. It was the first military action between the Kingdom of Spain and the Holy Roman Empire after the War of the Spanish Succession (1701–1714), and was the direct cause of the War of the Quadruple Alliance (1718–1720). The Spanish troops commanded by the Marquis of Lede and Don José Carrillo de Albornoz, 1st Duke of Montemar, supported by the Spanish fleet, defeated the Emperor's troops easily, and conquered the entire island of Sardinia, which had been ruled by the Emperor since the Treaty of Rastatt (1714), returning it again and for the final time to Spain.