The Protectorate was the period of the Commonwealth (or, to monarchists, the Interregnum) during which England and Wales, Scotland, Ireland and the English overseas possessions were governed by a Lord Protector as a republic. The Protectorate began in 1653, when the dissolution of the Rump Parliament and then Barebone's Parliament allowed Oliver Cromwell to be appointed Lord Protector of the Commonwealth under the terms of the Instrument of Government. In 1659, the Protectorate Parliament was dissolved by the Committee of Safety as Richard Cromwell, who had succeeded his father as Lord Protector, was unable to keep control of the Parliament and the Army. That marked the end of the Protectorate and the start of a second period of rule by the Rump Parliament as the legislature and the Council of State as the executive.
The Interregnum (literally meaning "between reign" in Latin) was the period between the execution of Charles I on 30 January 1649 and the arrival of his son Charles II in London on 29 May 1660 which marked the start of the Restoration. During the Interregnum, England was under various forms of republican government (see Commonwealth of England; this article describes other facets of the Interregnum).