Capell was the only son of Sir Henry Capell, of Rayne Hall, Essex, and his wife Theodosia Montagu, daughter of Sir Edward Montagu of Boughton House, Northamptonshire. He was educated at Queens' College, Cambridge. In April 1640, he was elected Member of Parliament for Hertfordshire in the Short Parliament, and was re-elected MP for Hertfordshire for the Long Parliament in November 1640. At first, he supported the opposition of the arbitrary government of King Charles I of England. On 5 December 1640, he delivered the "Petition from the county of Hertfordshire", outlining grievances against the King, and continued to criticise the King and the Kings advisers right through to the summer of 1641. In June 1641, in an effort to raise additional revenue, the price of baronies was reduced from £400 to £350, and Arthur Capell was raised to the peerage by the title of Baron Capell of Hadham, in the County of Hertford, on 6 August 1641. However, Capell was openly allying himself with the King's cause by early 1642, on which side his sympathies were now engaged. On the outbreak of the English Civil War, he was appointed lieutenant-general of Shropshire, Cheshire, and North Wales, where he rendered useful military services, and was later made one of the Councillors of Prince Charles Stewart, as well as a commissioner at the Treaty of Uxbridge in 1645. He attended the Queen, Henrietta Maria of France, in her flight to France in 1646, but disapproved of her son Prince Charles's journey thither, and afterwards retired to Jersey; later, he subsequently aided in the King's escape to the Isle of Wight. Capell was one of the chief Royalist leaders in the second Civil War, but met with no success, and on the 27 August 1648, together with Earl of Norwich, he surrendered to Lord Fairfax at Colchester, on the promise of quarter for life. This assurance was afterwards interpreted as not binding the civil authorities, and his fate for some time hung in the balance. He succeeded in escaping from the Tower of London, wading the moat once he had got over the walls, only to be betrayed by a Thames waterman, who had been engaged to row him from a hiding place at the Temple to one in Lambeth. He was again captured and was condemned to death by parliament, on 8 March 1649, and beheaded together with the Duke of Hamilton and the Earl of Holland. One of Lord Capell's last requests was for his heart to be buried with the body of King Charles I, and after his execution, Capell's heart was preserved in a silver box. The silver box was kept in the custody of the Bishop of Winchester, and was later presented, by the Bishop, to King Charles II. In 1703, a heart in a silver box was found at Hadham Hall, suggesting that the King sent the heart to Capell's son. It was later taken to Cassiobury, but since the dissolution and sale of the Cassiobury estate, the whereabouts of Capell's heart are now unknown. A memorial stone to Lord Capell was erected at St Cecelia's Church in Little Hadham, Hertfordshire.
Works
Capell wrote Daily Observations or Meditations: Divine, Morall, published with some of his letters in 1654, and reprinted, with a short life of the author, under the title Excellent Contemplations, in 1683.
Marriage and children
On 28 November 1627, Capell married Elizabeth Morrison, daughter and sole heiress of Sir Charles Morrison of Cassiobury, Hertfordshire, and Mary Hicks, who brought the Cassiobury estate, including Cassiobury House, into his family, making him one of the richest men in England. His lands were scattered across ten counties, and brought him a reputed annual income of £7,000. By his wife, he had four daughters and five sons, including:
Arthur Capell, 1st Earl of Essex, eldest son and heir, created Earl of Essex at the Restoration. When the Earl, facing charges of treason, committed suicide in 1683, King Charles II remarked that he should have known his life would be spared, for "his father died for mine".
