He married Maria Antonia of Spain ( 1729 â `` 1785 ) , youngest daughter of Philip V of Spain and Elisabeth Farnese , on 31 May 1750 at Oulx and later had twelve children . He married Infanta Maria Antonietta of Spain ( 1729 â `` 1785 ) , youngest daughter of Philip V of Spain and Elisabeth Farnese . They were married on 31 May 1750 at Oulx and later had twelve children .