Complex sentence: After his death in 1733, his sister Catalina Ventura, deceased 1739, became 9th Duchess of Veragua; but because she had married on 31 December 1716 Madrid James Francis FitzJames Stuart y Burgh, their children inherited Spanish and a few British titles.
Split into simpler sentences: After his death in 1733, his sister Catalina Ventura, deceased 1739, became 9th Duchess of Veragua. But because she had married on 31 December 1716 Madrid James Francis FitzJames Stuart y Burgh, their children inherited Spanish and a few British titles.