He abdicated in favor of his son , Ferdinando IV , on 21 July 1859 , but Ferdinando IV was never recognized in Tuscany , and was deposed by the government on 16 August . He abdicated in favor of his son , Ferdinando IV , on 21 July 1859 , but Ferdinando IV was never recognized in Tuscany , and was deposed by the provisional government on 16 August .