Oliver Cromwell (25 April 1599 – 3 September 1658) was an English military and political leader who overthrew the English monarchy and temporarily turned England into a republican Commonwealth, and served as Lord Protector of England, Scotland, and Ireland.

Cromwell was one of the commanders of the New Model Army which defeated the royalists in the English Civil War. After the execution of King Charles I in 1649, Cromwell dominated the short-lived Commonwealth of England, conquered Ireland and Scotland, and ruled as Lord Protector from 1653 until his death in 1658.

Cromwell was born into the ranks of the middle gentry, and remained relatively obscure for the first 40 years of his life. Along with his brother, Henry, he kept a smallholding of chickens and sheep, selling eggs and wool to support himself. His lifestyle resembled that of a yeoman farmer until he received an inheritance from his uncle. After undergoing a religious conversion during the same decade, Cromwell made an independent style of puritanism an essential part of his life. As a ruler he executed an aggressive and effective foreign policy and did as much as any English leader to shape the future of the land he governed. But his Commonwealth collapsed after his death and the royal family was restored in 1660. An intensely religious man—a self-styled Puritan Moses—he fervently believed God was guiding his victories. He was never identified with any one sect or position, however, and strongly favoured religious tolerance for all the various Protestant groups.