Complex sentence: He was married secondly to Mary Scott (died 1698), a Dutch heiress of Scots descent, and thirdly to Elizabeth Berkeley (née Blake), a religious writer of some note, who died in 1709.
Split into simpler sentences: He was married secondly to Mary Scott (died 1698), a Dutch heiress of Scots descent. He married thirdly Elizabeth Berkeley (née Blake), a religious writer of some note, who died in 1709.