In most hereditary monarchies and some elective monarchies, 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, abdicates or is deposed, or unless the monarchy itself is abolished. Other elective monarchies may have a fixed period of time for the duration of the monarch's tenure in office, with one notable example being the King of Malaysia.
The term of a reign can be indicated with the abbreviation "r." (for Latinregnavit/rexit) after a sovereign's name, such as the following:
Queen Wilhelmina of the Netherlands abdicated in 1948 in favor of her daughter Juliana, who then reigned until 1980 when she abdicated in favor of her daughter, Beatrix, who in turn abdicated in 2013 in favor of her son and heir apparent Willem-Alexander. In all three cases, the monarch lost the title of queen and became a princess after abdicating.
Abolition of monarchy
King Louis XVI of France reigned from 1774 until the overthrow of the monarchy in 1792 during the French Revolution. He was executed the following year.
Emperor Haile Selassie of Ethiopia reigned for over 40 years (1930–1974) until he was forced to abdicate by the Derg when it seized power in a coup, abolishing the 3,000 year old monarchy.