Regent

In a monarchy, a regent (|ruling, governing}}) is a person appointed to govern a state because the actual monarch is a minor, absent, incapacitated or unable to discharge their powers and duties, or the throne is vacant and a new monarch has not yet been determined. The rule of a regent or regents is called a regency. A regent or regency council may be formed ''ad hoc'' or in accordance with a constitutional rule. ''Regent'' is sometimes a formal title granted to a monarch's most trusted advisor or personal assistant. If the regent is holding the position due to their being in the line of succession, the compound term ''prince regent'' is often used; if the regent of a minor is their mother, and she is wife or widow of the king, she would be referred to as ''queen regent''.

If the formally appointed regent is unavailable or cannot serve on a temporary basis, a may be appointed to fill the gap.

In a monarchy, a regent usually governs due to one of these reasons, but may also be elected to rule during the period when the royal line has died out. This was the case in the Kingdom of Finland and the Kingdom of Hungary, where the royal line was considered extinct in the aftermath of World War I. In Iceland, the regent represented the King of Denmark as sovereign of Iceland until the country became a republic in 1944. In the Polish–Lithuanian Commonwealth (1569–1795), kings were elective, which often led to a fairly long interregnum. During this period, the Roman Catholic primate (the Archbishop of Gniezno) served as the regent, and was called (Latin: ruler 'between kings' as in Ancient Rome). In the small republic of San Marino, the two Captains Regent () are both elected for a six-month term as joint heads of state.

Famous regency periods include that of the Prince Regent, later George IV of the United Kingdom, giving rise to many terms such as Regency era and Regency architecture. Strictly, this period lasted from 1811 to 1820, when his father George III was insane, though when used as a period label it generally covers a wider period. Philippe II, Duke of Orléans was Regent of France from the death of Louis XIV in 1715 until Louis XV came of age in 1723; this is also used as a period label for many aspects of French history, as in French, again tending to cover a rather wider period than the actual regency. In the 16th century, Queen Catherine de Medici's acts as regent caused her to become arguably the most important woman in Europe, giving her name to an age. The equivalent Greek term is (), meaning overseer.

Liechtenstein (under Alois, Hereditary Prince of Liechtenstein) and Luxembourg (under Guillaume, Hereditary Grand Duke of Luxembourg) are the only countries with active regencies. In 2016, Prem Tinsulanonda became the oldest regent of any nation, at the age of 96. He became the regent for Rama X of Thailand, who chose not to formally accede to the throne until the end of the mourning period for his father. Previously, this record was held by Prince Regent Luitpold of Bavaria, who was 91 at the end of his regency. Provided by Wikipedia