Complex sentence: Purbeck, whose insanity was intermittent, married, as his second wife, Elizabeth, daughter of Sir William Slingsby of Kippax, West Yorkshire, and died without legitimate issue on 18 Feb.1656--7 at Charlton, near Greenwich.
Split into simpler sentences: Purbeck, whose insanity was intermittent, married, as his second wife, Elizabeth, daughter of Sir William Slingsby of Kippax, West Yorkshire. He died without legitimate issue on 18 February 1656--7 at Charlton, near Greenwich.