During the war of the Mantuan Succession, Cardinal Richleu sent a French army under the command of Montmorency to invade Savoy to attempt to influence the Mantuan succession. This was the cause casus belli but his primary motive was to force Charles Emmanuel I, Duke of Savoy from his alliance the Habsburgs (Philip IV of Spain and Ferdinand II, Holy Roman Emperor) and hence sever the land link between Habsburg lands in Italy and those in Germany and the Spanish Netherlands.