In 1627 Sir Charles Morrison's daughter, Elizabeth (the heir to Cassiobury), married Arthur Capell, 1st Baron Capell of Hadham (1610–1649) and the estate passed into the Capel family. The Capels were settled at Little Hadham in Hertfordshire, but after the marriage they became closely associated with Cassiobury. Arthur Capel was a politician and a supporter of the Royalist cause in the English Civil War; during Cromwell's rise to power, Capel was tried and condemned to death by the Parliamentarians, and beheaded in May 1649.