|Count / Earl|
A prince regent, or prince-regent, is a prince who rules a monarchy as regent instead of a monarch, e.g., as a result of the Sovereign's incapacity (minority or illness) or absence (remoteness, such as exile or long voyage, or simply no incumbent). While the term itself can have the generic meaning and refer to any prince who fills the role of regent, historically it has mainly been used to describe a small number of individual Princes who were Regents.
Prince Regent in the United Kingdom 
In the English language the title Prince Regent is most commonly associated with George IV, who held the style HRH The Prince Regent during the incapacity, by dint of mental illness, of his father, George III (see Regent for other regents). Regent's Park and Regent Street in London are named after him.
This period is known as the British Regency, or just the Regency.
The title was conferred by the Regency Act on February 5, 1811. Subject to certain limitations for a period, the Prince Regent was able to exercise the full powers of the King. The precedent of the Regency Crisis of 1788 (from which George III recovered before it was necessary to appoint a Regent) was followed. The Prince of Wales continued as regent until his father's death in 1820, when he became George IV.
Prince Regent in Germany 
In Germany, the title Prinzregent (literally prince regent) is most commonly associated with Prince Luitpold of Bavaria, who served as regent for two of his nephews, King Ludwig II of Bavaria, who was declared mentally incompetent in 1886, and King Otto of Bavaria (who had been declared insane in 1875) from 1886 until 1912.
The years of Luitpold's regency were marked by tremendous artistic and cultural activity in Bavaria, where they are known after the regencies as the Prinzregentenjahre or the Prinzregentenzeit. Numerous streets in Bavarian cities and towns are called Prinzregentenstraße. Many institutions are named in Luitpold's honour, e.g., the Prinzregententheater in Munich. Prinzregententorte is a multi-layered cake with chocolate butter cream named in Luitpold's honour.
At Luitpold's death in 1912, his son Prince Ludwig succeeded as Prince Regent. Ludwig held the title for less than a year, since the Bavarian Legislature decided to recognise him as king.
Prince Regent in Belgium 
- The first head of state of Belgium after it seceded from the Dutch monarchy in 1831 was a regent (but not a prince in his own right), baron Erasme Louis Surlet de Chokier, before the new nation, which had chosen to become a parliamentary monarchy, had its first king sworn in to the constitution.
- Prince Charles of Belgium served as Prince Regent of Belgium from 1944 to 1950 during the German captivity and then exile to Switzerland of his elder brother, King Leopold III of Belgium.
Prince Regent in Bulgaria 
Prince Kiril of Bulgaria was appointed head of a regency council by the Bulgarian parliament following the death of his brother, Tsar Boris on 28 August 1943, to act as Head of State until the late Tsar's son, Simeon II of Bulgaria, became 18. On 5 September 1944 the Soviet Union declared war on the Kingdom of Bulgaria and on the 8th - Soviet armies crossed the Romanian border and occupied the country. On 1 February 1945 the prince regent Kyril, and the two other former regents - Professor Bogdan Filov and General Nikola Mihov, as well as a range of former cabinet ministers, royal advisors and 67 MPs were executed.
Prince Lieutenant in Luxembourg 
The heir to the grand duke of Luxembourg may be titled prince-lieutenant ('prince deputy') during a period in which the incumbent remains formally on the grand ducal throne, but (progressively, most) functions of the crown are performed by the 'monarch apprentice', as prince Jean (still alive) did 4 May 1961 - 12 November 1964 in the last years of his mother Charlotte's reign (she lived until 1985), and Jean's own son prince Henri 3 March 1998 - 7 October 2000 until his father abdicated and he succeeded.
King or Queen regent 
It has also been known throughout history that when a king is unable to reign or is out of the country for long periods of time, sometimes the consort will step up and will temporarily do the duties of a Prince regent. Sometimes they are unofficially known as regents themselves. In the Kingdom of Swaziland, queen mothers have temporarily stepped in when the sovereign was either a minor or unable to reign for other reasons.
Other notable Princes regent 
- More prince-regents (often without such specific title) are to be found in Regent.
- Crown Prince Frederick of Denmark served as regent from 1784 to 1808 for his father, King Christian VII of Denmark, who was insane.
- Prince William of Prussia served as regent from 1858 to 1861 for his older brother King Frederick William IV of Prussia, who had become mentally unfit to rule.
- Prince Charles, Count of Flanders, served as regent from 1944 to 1950 for his older brother king Leopold III of Belgium, whose position had come under scrutiny after the Second World War and his marriage to Lilian Baels.
- Prince Dorgon of the Qing Dynasty served as regent for his nephew, Emperor Shunzhi, from 1643 to 1650, because the latter was only six at the time of his ascension. Dorgon was instrumental in moving Manchu forces into Beijing in 1644, proclaiming the Qing dynasty to be the legitimate successor to the Ming Dynasty. In Qing Dynasty historical records, Dorgon was the first to be referred to as Shezhengwang 摄政王(The Prince Regent).
- Zaifeng, Prince Chun during the Qing Dynasty served as regent from 1908 to 1911 for his young son Puyi, the Xuantong Emperor. Apart from Dorgon, Zaifeng was the only person in Chinese history who was specifically referred to as Prince Regent.
- Prince Paul of Yugoslavia from 1934 to 1941, known in Serbian as Његово Краљевско Височанство, Кнез Намесник (English: His Royal Highness The Prince Regent)
- John, Prince of Brazil (1767–1826) served as regent of Portugal for his mother Queen Maria I, who had become mentally unfit to rule, from 1799 to 1816. His regency was associated with the famous transfer of the Portuguese court to Brazil.