The British Parliament is the supreme legislative body in the United Kingdom, established on 15 June 1215 under the Magna Carta. The Parliament originally consisted solely of the House of Lords, but the elected House of Commons was created on 20 January 1265. Over the centuries, the Parliament progressively limited the power of the monarchy, culminating in the English Civil War of 1642-1651, during which the Parliamentarians rebelled against the royalist Cavaliers and briefly established the republican English Commonwealth under the brutal military dictator Oliver Cromwell. After the restoration of Charles II of England in 1660 and the Glorious Revolution of 1688, the supremacy of the Parliament was a settled principle, and all future British monarchs were forced to abide by a constitution. By the 21st century, power was vested in the hands of the House of Commons (the lower house), with the House of Lords upper house having delaying powers and the monarch being essentially forced to take the Prime Minister's advice. By 2017, Parliament had 1,452 seats, with 802 being Lords Temporal and Lords Spiritual and 650 being Members of Parliament (MPs).