Complex sentence: He was succeeded by his son, the aforementioned fourth Earl, who was raised to Duke in 1694; together with Lady Margaret he had one daughter but no sons and on his death in 1711 all his titles became extinct.
Split into simpler sentences: He was succeeded by his son, the aforementioned fourth Earl, who was raised to Duke in 1694. The Duke of Newcastle upon Tyne had one daughter but no sons and on his death in 1711 all his titles became extinct.