Heir apparent in the context of "Naruhito"

Michael I (Romanian: Mihai I [miˈhaj]; 25 October 1921 – 5 December 2017) was the last king of Romania, reigning from 20 July 1927 to 8 June 1930 and again from 6 September 1940 until his forced abdication on 30 December 1947.

Shortly after Michael's birth, his father, Crown Prince Carol, had become involved in a controversial relationship with Magda Lupescu. In 1925, Carol was pressured to renounce his rights (in favour of his son Michael) to the throne and moved to Paris in exile with Lupescu. In July 1927, following the death of his grandfather Ferdinand I, Michael ascended the throne at age five, the youngest crowned head in Europe. As Michael was still a minor, a regency council was instituted, composed of his uncle Prince Nicolas, Patriarch Miron Cristea and Chief Justice Gheorghe Buzdugan. The council proved to be ineffective and, in 1930, Carol returned to Romania and replaced his son as monarch, reigning as Carol II. As a result, Michael returned to being heir apparent to the throne and was given the additional title of Grand Voievod of Alba-Iulia.

Bashar al-Assad (born 11 September 1965) is a Syrian former politician, doctor and military officer who served as the president of Syria from 2000 until his overthrow in 2024 after the Syrian civil war. As president, Assad was commander-in-chief of the Syrian Arab Armed Forces and secretary-general of the Central Command of the Arab Socialist Ba'ath Party. He is the son of Hafez al-Assad, who ruled Syria from 1970 to 2000.

In the 1980s, Assad became a doctor, and in the early 1990s he was training in London as an ophthalmologist. In 1994, after his elder brother Bassel al-Assad died in a car crash, Assad was recalled to Syria to take over Bassel's role as heir apparent. Assad entered the military academy and in 1998 took charge of the Syrian occupation of Lebanon begun by his father. On 17 July 2000, Assad became president, succeeding his father, who had died on 10 June 2000. Hopes that the UK-educated Assad would bring reform to Syria and relax the occupation of Lebanon were dashed following a series of crackdowns in 2001–2002 that ended the Damascus Spring, a period defined by calls for transparency and democracy. Assad's rule would become more repressive than his father's.

Charles III (Charles Philip Arthur George; born 14 November 1948) is King of the United Kingdom and 14 other Commonwealth realms.

Charles was born during the reign of his maternal grandfather, King George VI, and became heir apparent when his mother, Queen Elizabeth II, acceded to the throne in 1952. He was created Prince of Wales in 1958 and his investiture was held in 1969. Charles was educated at Cheam School and Gordonstoun, and later spent six months at the Timbertop campus of Geelong Grammar School in Victoria, Australia. After completing a history degree from the University of Cambridge, he served in the Royal Air Force and the Royal Navy from 1971 to 1976. He married Lady Diana Spencer in 1981 and they had two sons, William and Harry. Charles and Diana divorced in 1996 after years of estrangement and well-publicised extramarital affairs. Diana died the following year from injuries sustained in a car crash. In 2005, Charles married his long-time partner, Camilla Parker Bowles.

Henry Frederick, Prince of Wales KG (19 February 1594 – 6 November 1612) was the eldest son and heir apparent of King James VI and I and Anne of Denmark. His name derives from his grandfathers: Henry Stuart, Lord Darnley; and Frederick II of Denmark. Prince Henry was widely seen as a bright and promising heir to the English, Irish, and Scottish thrones. However, at the age of 18, he predeceased his father, dying of typhoid fever. His younger brother, the future Charles I, succeeded him as heir apparent to the thrones.

Edward VII (Albert Edward; 9 November 1841 – 6 May 1910) was King of the United Kingdom and the British Dominions, and Emperor of India, from 22 January 1901 until his death in 1910.

The second child and eldest son of Queen Victoria and Prince Albert of Saxe-Coburg and Gotha, Edward, nicknamed "Bertie", was Prince of Wales and heir apparent to the British throne for almost 60 years. During his mother's long reign, he was largely excluded from political influence and came to personify the leisured elite. He married Princess Alexandra of Denmark in 1863; the couple had six children. As Prince of Wales, Edward travelled throughout Britain performing ceremonial public duties and represented Britain on visits abroad. His tours of North America in 1860 and of the Indian subcontinent in 1875 proved popular successes. Despite this public approval, his reputation as a playboy prince soured his relationship with his mother.

Ferdinand VII (Spanish: Fernando VII; 14 October 1784 – 29 September 1833) was King of Spain during the early 19th century. He reigned briefly in 1808 and then again from 1813 to his death in 1833. Before 1813, he was known as el Deseado (the Desired), and after, as el Rey Felón (the Criminal King).

Born in Madrid at El Escorial, Ferdinand was heir apparent to the Spanish throne in his youth. Following the 1808 Tumult of Aranjuez, he ascended the throne. That year Napoleon overthrew him; he linked his monarchy to counter-revolution and reactionary policies that produced a deep rift in Spain between his forces on the right and liberals on the left. Back in power in December 1813, he re-established the absolutist monarchy and rejected the liberal constitution of 1812. A revolt in 1820 led by Rafael del Riego forced him to restore the constitution, starting the Liberal Triennium, a three-year period of liberal rule. In 1823, the Congress of Verona authorised a successful French intervention, restoring him to absolute power for the second time. He suppressed the liberal press from 1814 to 1833, jailing many of its editors and writers.

The monarchy of Norway is the system used in Norway by which a hereditary monarch reigns as head of state under a constitutional monarchy with a parliamentary system. The Norwegian monarchy can trace its line back to the reign of Harald Fairhair and the previous petty kingdoms which were united to form Norway; it has been in unions with both Sweden and Denmark for long periods.

The present monarch is King Harald V, who has reigned since 17 January 1991, succeeding his father, Olav V. The heir apparent is his only son, Crown Prince Haakon. The crown prince undertakes various public ceremonial functions, as does the king's wife, Queen Sonja. The crown prince also acts as regent in the king's absence. There are several other members of the royal family, including the king's daughter, grandchildren and sister. Since the dissolution of the union between Norway and Sweden and the subsequent election of a Danish prince as King Haakon VII in 1905, the reigning royal house of Norway has been a branch of the Schleswig-Holstein-Sonderburg-Glücksburg branch of the House of Oldenburg; originally from modern-day Schleswig-Holstein in Germany, agnatically (through Prince Philip) the same royal house as the British (since the accession of Charles III), Danish and former Greek royal families.

George VI (Albert Frederick Arthur George; 14 December 1895 – 6 February 1952) was King of the United Kingdom and the Dominions of the British Commonwealth from 11 December 1936 until his death in 1952. He was also the last Emperor of India from 1936 until the British Raj was dissolved in August 1947, and the first Head of the Commonwealth following the London Declaration of 1949.

The future George VI was born during the reign of his great-grandmother Queen Victoria; he was named Albert at birth after his late great-grandfather Prince Albert of Saxe-Coburg and Gotha and was known as "Bertie" to his family and close friends. His father ascended the throne as George V in 1910. As the second son of the king, Albert was not expected to inherit the throne. He spent his early life in the shadow of his elder brother, Edward, the heir apparent. Albert attended naval college as a teenager and served in the Royal Navy and Royal Air Force during the First World War. In 1920, he was made Duke of York. He married Lady Elizabeth Bowes-Lyon in 1923, and they had two daughters, Elizabeth and Margaret. In the mid-1920s, he engaged speech therapist Lionel Logue to treat his stutter, which he learned to manage to some degree. His elder brother ascended the throne as Edward VIII after their father died in 1936, but Edward abdicated later that year to marry the twice-divorced American socialite Wallis Simpson. As heir presumptive to Edward VIII, Albert became king, taking the regnal name George VI.