List of chief governors of Ireland
The office of chief governor of Ireland existed under various names from the 12th-century Norman invasion to the creation of the Irish Free State on 6 December 1922. Common names were (Chief) justiciar (13th–14th centuries); (King's) lieutenant (14th–16th century); (Lord) Deputy (15th–17th centuries), and Lord Lieutenant (standard after 1690). The unofficial term Viceroy was also common. Reasons for difficulty in stating terms of office include that many left the office empty for a period (sometimes to return to the Court of St. James's, sometimes to return to their British estates) before  either being replaced or returning. There is difficulty in getting clear information before 1529; in the earlier years, there were frequent long vacancies, during which a Lord Deputy or Lord Justice would act as chief governor. The Irish Act of Union merged the Kingdom of Ireland with the Kingdom of Great Britain to form the United Kingdom of Great Britain and Ireland. The new United Kingdom came into being on 1 January 1801 resulting in the disappearance of the separate Irish Parliament: Though many expected the office of Lord Lieutenant to be abolished, it survived. Periodic debates throughout the nineteenth  century erupt over whether it should be replaced by a 'Secretary of State for Ireland'. The office of Chief Secretary for Ireland (in effect number two in Irish government ranking) grows in importance, with the Lord Lieutenant gradually reduced to a largely though not completely ceremonial role. The office was replaced by the Governor-General of the Irish Free State. In Northern Ireland the position was replaced by that of Governor of Northern Ireland. Medieval. "Source":