Question: In which year did this English military and political leader and later Lord Protector of the Commonwealth of England, Scotland, and Ireland, whom William Govan was accused of supporting, die?

Context paragraphs:
Cromwell's Act of Grace: Cromwell's Act of Grace or more formally the Act of Pardon and Grace to the People of Scotland, was proclaimed at the Mercat Cross in Edinburgh on 5 May 1654.  General George Monck, the English Military Governor of Scotland, was present in Edinburgh, having arrived the day before for two proclamations also delivered at the Mercat Cross, the first declaring Oliver Cromwell to be the Protector of England Ireland and Scotland, and that Scotland was united with the Commonwealth of England.

Oliver Cromwell in popular culture: Oliver Cromwell (25 April 1599 – 3 September 1658) was an English military and political leader and later Lord Protector of the Commonwealth of England, Scotland and Ireland.

Statue of Oliver Cromwell, Westminster: A statue of Oliver Cromwell stands outside the House of Commons of the United Kingdom in Westminster, London.  It is a sculpture of Oliver Cromwell, Lord Protector of the Commonwealth of England, Scotland and Ireland.  The statue was designed by Hamo Thornycroft and erected in 1899.  It has divided opinion, both before its erection and since, due to Cromwell's opposition to the British monarchy and his role in the conquest of Ireland.  Cromwell stands accused by some of war crimes, religious persecution and ethnic cleansing on a dramatic scale against Catholics in Ireland.

Cromwell (disambiguation): Oliver Cromwell (1599–1658) was an English military and political leader and later Lord Protector of the Commonwealth of England, Scotland and Ireland.

William Govan: Captain William Govan (1623–1661).  was a Scottish officer who fought for the Covenanters during the Wars of the Three Kingdoms.  He was awarded the honour of presenting Montrose's standard to the Scottish Parliament in 1650.  He was accused of deserting the Scottish army later the same year and supporting the English New Model Army under the command of Oliver Cromwell, which was at that time invading Scotland.  On 1 June 1661, the year after the restoration of the monarchy, and a few days after he was found guilty of treason, he was hanged as a traitor next to the Mercat Cross in Edinburgh and his head was put on a spike and displayed at West Port, Edinburgh.

Anne Seymour, Duchess of Somerset: Anne Seymour, Duchess of Somerset (née Stanhope) (c.1497 – 16 April 1587) was the second wife of Edward Seymour, 1st Duke of Somerset (c.1500–1552), who held the office of Lord Protector during the first part of the reign of his nephew King Edward VI, through whom Anne was briefly the most powerful woman in England.  During her husband's time as Lord Protector she claimed precedence over the dowager queen Catherine.

Oliver Cromwell: Oliver Cromwell (25 April 15993 September 1658) was an English military and political leader and later Lord Protector of the Commonwealth of England, Scotland, and Ireland.

Oliver Cromwell (disambiguation): Oliver Cromwell (1599–1658) was an English military and political leader and later Lord Protector of the Commonwealth of England, Scotland and Ireland.

Barebone's Parliament: Barebone's Parliament, also known as the Little Parliament, the Nominated Assembly and the Parliament of Saints, came into being on 4 July 1653, and was the last attempt of the English Commonwealth to find a stable political form before the installation of Oliver Cromwell as Lord Protector.  It was an assembly entirely nominated by Oliver Cromwell and the Army's Council of Officers.  It acquired its name from the nominee for the City of London, Praise-God Barebone.  The Speaker of the House was Francis Rous.  The total number of nominees was 140, 129 from England, five from Scotland and six from Ireland (see the list of MPs).

The Protectorate: The Protectorate was the period during the Commonwealth (or, to monarchists, the Interregnum) when England and Wales, Ireland and Scotland were governed by a Lord Protector.  The Protectorate began in 1653 when, following the dissolution of the Rump Parliament and then Barebone's Parliament, Oliver Cromwell was 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.  This 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.

Supporting paragraphs: William Govan Oliver Cromwell
Answer: 1658