A Quadruple Alliance of Britain, France, Austria and the Netherlands was organized on 2 August 1718 to stop him. In the Treaty of The Hague, signed on 17 February 1720, Philip renounced his conquests of Sardinia and Sicily, but assured the ascension of his eldest son by Elisabeth to the Duchy of Parma upon the reigning duke's death. Philip abdicated in January 1724 in favor of Louis I, his eldest son with his first wife, but Louis died in August and Philip resumed the crown.