Spencer Compton was the eldest son of Sir William Compton, a Warwickshire gentleman and his wife Elizabeth, daughter and heiress of Sir John Spencer. After attending Queen's College, Cambridge, he was knighted in 1616 and granted the title Lord Compton when his father was elevated to the peerage as first Earl of Northampton in 1618. He married Mary Beaumont, a cousin of the Marquis (later Duke) of Buckingham in 1621. Compton accompanied Prince Charles (later Charles I) and Buckingham when they visited Madrid in 1623 in an attempt to arrange a marriage between Charles and the King of Spain's sister. He remained a close personal friend of Charles. Compton succeeded as the second Earl of Northampton on the death of his father In 1630. Along with large estates in the Midlands and London, he also assumed his father's position as Lord-Lieutenant of Warwickshire and Gloucestershire.
Northampton gained military experience in the European wars, serving in George Goring's regiment at the siege of Breda in 1637 and fighting for the Elector Palatine at the battle of Vlotho in 1638. He raised troops for the King in the Bishops' Wars of 1639-40. During the summer of 1642, Northampton was appointed Commissioner of Array for the counties of Warwickshire, Northamptonshire and Gloucestershire. At the end of July, Northampton called out the Warwickshire Trained Bands and confronted Lord Brooke as he moved a convoy of artillery from London to Warwick Castle. After heated negotiations, Brooke agreed to leave the artillery at Banbury in Oxfordshire and each side promised to give the other three days' notice of any attempt to remove it. A week later however, Northampton took advantage of Brooke's absence in London to seize the artillery and use it to besiege Warwick Castle. On 22 August — the day that King Charles raised his standard at Nottingham — Northampton's troops were defeated by Brooke's relief force and the siege lifted.
Northampton joined the King's army and fought at Edgehill in October 1642, then secured Banbury as the northernmost of the defensive ring of Royalist strongholds around Oxford.
In February 1643, Northampton was commissioned commander of Royalist forces in Warwickshire and Northamptonshire. After the fall of Lichfield in March, Northampton joined forces with Colonel-General Henry Hastings to prevent the Parliamentarian commanders Gell and Brereton from capturing Stafford. Northampton attacked the Parliamentarian army at Hopton Heath near Stafford on 19 March. During the battle he was unhorsed and separated from his troops. Surrounded by enemies, Northampton refused to surrender to "base rogues and rebels" and was killed by a halberd blow to the head. His body was removed from the field by the retreating Parliamentarians. Sir John Gell refused to return it unless the Royalists surrendered the artillery captured during the battle. When Northampton's son refused to return the artillery or to refund the money Gell had paid to embalm the body, the corpse was paraded through the streets of Derby before being buried at All Hallows Church. It was subsequently reburied at Northampton's ancestral home at Compton Wynyates in Warwickshire.
References:
Martyn Bennett, Spencer Compton, second earl of Northampton, Oxford DNB, 2004
Stuart Reid, All the King's Armies, 1998