The sitter was the son of Robert Devereux, 2nd Earl of Essex. He was born in 1591 and educated at Eton and Merton College Oxford. On his father's death in 1601 he continued to be styled Viscount Hereford until an act of Parliament in 1604 restored to him the titles of Earl of Essex, Viscount Hereford, Lord Ferrers and Lord Bourchier. In 1642 he abandoned his allegiance to the King and was made "General of the Army of the Parliament", a post he retained until April 1645. Essex married firstly in 1606 Frances, daughter of Thomas Howard, Earl of Suffolk but they were divorced in 1613. He marrried secondly in 1631 Elizabeth, daughter of Sir William Paulet of Eddington, Wiltshire, dying without issue in 1646, when the Earldom of Essex became extinct.