Overview
A reign is the period of a person's or dynasty's occupation of the office of monarch of a nation (e.g., Saudi Arabia, Belgium, Andorra), of a people (e.g., the Franks, the Zulus) or of a spiritual community (e.g., Catholicism, Tibetan Buddhism, Nizari Ismailism). In most hereditary monarchies and some elective monarchies (e.g., Holy Roman Empire) there have been no limits on the duration of a sovereign's reign or incumbency, nor is there a term of office. Thus, a reign usually lasts until the monarch dies, unless the monarchy itself is abolished or the monarch abdicates or is deposed.
In elective monarchies, there may be a fixed period of time for the duration of the monarch's tenure in office (e.g., Malaysia).
The term of a reign can be indicated with the abbreviation "r." (for Latin ) after a sovereign's name, such as the following:
George VI, King of Great Britain, Ireland and the British Dominions, Emperor of India (r. 1936–1952)
Regnal periods
Notable reigns have included the following.
Queen Victoria of the United Kingdom of Great Britain and Ireland, Empress of India reigned from 1837 to 1901.
King Victor Emmanuel III of Italy reigned from 1900 to 1946.
King Bhumibol Adulyadej of Thailand reigned from 1946 to 2016.
Queen Elizabeth II of the Commonwealth realms reigned from 1952 to 2022.
Pope John XXIII reigned from 1958 to 1963.
Emperor Akihito of Japan reigned from 1989 to 2019.
From Wikipedia (CC BY-SA 4.0).