William Penn was born in 1644 at Tower Hill, London, the son of English Admiral Sir William Penn, and Margaret Jasper, from a Dutch family, previously the widow of a Dutch captain, and the daughter of a rich merchant from Rotterdam.[5] William Penn, Sr. served in the Commonwealth Navy during the English Civil War and was rewarded by Oliver Cromwell with estates in Ireland. The lands were seized from Irish Catholics in retaliation for the failed Irish Rebellion of 1641. Admiral Penn took part in the restoration of Charles II and was eventually knighted and served in the Royal Navy. At the time of his son's birth, Captain Penn was twenty-three and an ambitious naval officer in charge of quelling Irish Catholic unrest and blockading Irish ports.[6]