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 the Commonwealth of England, Cromwell ruled as Lord Protector from December 1653 until his death.

Although elected Member of Parliament (MP) for Huntingdon in 1628, much of Cromwell's life prior to 1640 was marked by financial and personal 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 he 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 Thomas Fairfax, and played a key role in winning the English Civil War.

The death of Charles I and exile of his son Charles, followed by military victories in Ireland and in 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, when he was succeeded by his son Richard, whose weakness led to a power vacuum.