Oliver Cromwell (25 April 1599 – 3 September 1658) was an English statesman, politician, and soldier, widely regarded as one of the most important figures in British history. He came to prominence during the Wars of the Three Kingdoms, initially as a senior commander in the Parliamentarian army and latterly as a politician. A leading advocate of the execution of Charles I in January 1649, which led to the establishment of Commonwealth of England, he ruled as Lord Protector from December 1653 until his death in September 1658.

Although elected MP for Huntingdon in 1628, much of Cromwell's life prior to 1640 was marked by failure. He briefly contemplated emigration to New England, but became a religious Independent in the 1630s and thereafter believed his successes were the result of divine providence. In 1640, Cromwell was returned as MP for Cambridge in the Short and Long Parliaments. He joined the Parliamentarian army when the First English Civil War began in August 1642, and quickly demonstrated his military abilities. In 1645, he was appointed commander of the New Model Army cavalry under Sir Thomas Fairfax, and played a key role in winning the English Civil War.

The death of Charles I and exile of his son, followed by military victories in Ireland and Scotland, firmly established the Commonwealth and Cromwell's dominance of the new regime. In December 1653, he was named Lord Protector, a position he retained until his death in September 1658, when he was succeeded by his son Richard, whose weakness led to a power vacuum.