Crown prince in the context of "Emperor Yang of Sui"

An heir apparent is a person who is first in the order of succession and cannot be displaced from inheriting by the birth of another person. A person who is first in the current order of succession but could be displaced by the birth of a more eligible heir is known as an heir presumptive.

Today these terms most commonly describe heirs to hereditary titles (e.g. titles of nobility) or offices, especially when only inheritable by a single person. Most monarchies refer to the heir apparent of their thrones with the descriptive term of crown prince or crown princess, but they may also be accorded with a more specific substantive title: such as Prince of Orange in the Netherlands, Duke of Brabant in Belgium, Prince of Asturias in Spain (also granted to heirs presumptive), or the Prince of Wales in England and Wales; former titles include Dauphin in the Kingdom of France, and Tsesarevich in Imperial Russia.

Akihito (born 23 December 1933) is a member of the Imperial House of Japan who reigned as the 125th emperor of Japan from 7 January 1989 until his abdication on 30 April 2019. The era of his rule was named the Heisei era, Heisei being an expression of achieving peace worldwide.

Akihito was born as the fifth child and first son of Emperor Shōwa and Empress Kōjun. During the Second World War, he moved out of Tokyo with his classmates and remained in Nikkō until the surrender of Japan. In 1952, his Coming-of-Age ceremony and investiture as crown prince were held, and he began to undertake official duties in his capacity as crown prince. The next year, he made his first journey overseas and represented Japan at the coronation of Elizabeth II in London. He completed his university education in 1956. In April 1959, he married Michiko Shōda, a commoner; it was the first imperial wedding to be televised in Japan, drawing about 15 million viewers. The couple has three children: Naruhito, Fumihito, and Sayako.

Li Chongrun (Chinese: 李重潤; pinyin: Lǐ Chóngrùn; c.2 March 682 – October 8, 701), né Li Chongzhao (Chinese: 李重照; pinyin: Lǐ Chóngzhào), formally Crown Prince Yide (Chinese: 懿德太子; pinyin: Yìdé Tàizǐ ), was an imperial prince of the Tang dynasty and Wu Zetian's Zhou dynasty. He was the only son of Emperor Zhongzong (Li Zhe/Li Xian) and Emperor Zhongzong's second wife Empress Wei. In 701, he offended his grandmother Wu Zetian by discussing Wu Zetian's lovers Zhang Yizhi and Zhang Changzong with his sister Li Xianhui the Lady Yongtai and her husband Wu Yanji (武延基) the Prince of Wei, and he, along with Li Xianhui and Wu Yanji, were forced to commit suicide. He was posthumously honored as crown prince after his father Emperor Zhongzong was restored to the throne in 705 and in 706, Emperor Zhongzong provided Li Chongrun with an honorable burial by interring his remains at the Qianling Mausoleum.

Hirohito (裕仁; 29 April 1901 – 7 January 1989), posthumously honored as Emperor Shōwa (昭和天皇, Shōwa Tennō), was the 124th emperor of Japan according to the traditional order of succession, reigning from 1926 until his death in 1989. He remains the longest-reigning emperor in Japanese history and one of the longest-reigning monarchs in the world. As emperor during the Shōwa era, Hirohito presided over the rise of Japanese militarism, Japan's invasion of mainland Asia, the outbreak of the Second Sino-Japanese War, the Second World War, and the nation's postwar economic miracle.

Hirohito was born during the reign of his paternal grandfather, Emperor Meiji, as the first child of Crown Prince Yoshihito and Crown Princess Sadako (later Emperor Taishō and Empress Teimei). When Emperor Meiji died in 1912, Hirohito's father ascended the Chrysanthemum Throne, and Hirohito was proclaimed Crown Prince of Japan in 1916, making him the heir apparent. In 1921, he made an official visit to the United Kingdom and Western Europe, marking the first time a Japanese crown prince had traveled abroad. Due to his father's ill health, Hirohito became Sesshō of Japan (regent) that same year. In 1924, he married Princess Nagako Kuni, with whom he later had seven children: Shigeko, Sachiko, Kazuko, Atsuko, Akihito, Masahito and Takako. He became emperor upon his father's death in 1926.

The lordship of Piedmont, later the principality of Piedmont (Italian: Piemonte), was originally an appanage of the County of Savoy, and as such its lords were members of the Achaea branch of the House of Savoy. The title was inherited by the elder branch of the dynasty in 1418, at about which time Savoy was elevated to ducal status and Piedmont to princely status. When the House of Savoy was given the Kingdom of Sardinia, the Savoyards used the style of Prince of Piedmont (Italian: Principe di Piemonte) for their heir apparent. This first came into use by Prince Victor Amadeus of Savoy.

The usage was retained when Victor Emmanuel II became King of Italy, "Prince of Piedmont" becoming roughly equivalent to the British "Prince of Wales", the title bestowed to the Crown prince.

Princess is a title used by a female member of a regnant monarch's family or by a female ruler of a principality. The male equivalent is a prince (from Latin princeps, meaning principal citizen). Most often, the term has been used for the consort of a prince, or for the daughter of a monarch. A crown princess can be the heir apparent to the throne or the spouse of the heir apparent.

Princess Märtha of Sweden (Märtha Sofia Lovisa Dagmar Thyra; 28 March 1901 – 5 April 1954) was Crown Princess of Norway as the spouse of the future King Olav V from 1929 until her death in 1954. As Olav only became king in 1957, Märtha never became Queen of Norway. Her son, Harald V, is the current king of Norway. Princess Märtha was also an elder sister of Queen Astrid of Belgium and a maternal aunt of Grand Duchess Joséphine-Charlotte of Luxembourg and Kings Baudouin and Albert II of Belgium.

In 1940, Crown Princess Märtha and her family were immersed in World War II as Germany invaded Norway. After escaping to her home country of Sweden, and then being evacuated to America by President Franklin D. Roosevelt, she effectively advocated for Norway and did fundraising until the end of the war. In 1942, King Haakon VII of Norway, Märtha's father-in-law, invested her as a Dame Grand Cross of the Royal Norwegian Order of Saint Olav.

Margrethe II abdicated as Queen of Denmark on 14 January 2024, the 52nd anniversary of her accession, being the first voluntary abdication of a Danish monarch since that of Eric III in 1146.

Margrethe made the announcement of her abdication during her New Year's Eve address on 31 December 2023. On 14 January, Margrethe signed a declaration of her abdication during a meeting of the Council of State, whereafter her elder son Crown Prince Frederik succeeded to the Danish throne as King Frederik X. Per Danish state custom, the prime minister of Denmark then proclaimed the accession of the new monarch from the balcony of Christiansborg Palace.

Frederik IX (Christian Frederik Franz Michael Carl Valdemar Georg; 11 March 1899 – 14 January 1972) was King of Denmark from 1947 to 1972.

Frederik was born into the House of Glücksburg during the reign of his great-grandfather King Christian IX. He was the first child of Prince Christian of Denmark and Princess Alexandrine of Mecklenburg-Schwerin (later King Christian X and Queen Alexandrine). He became crown prince when his father succeeded as king in 1912. As a young man, he was educated at the Royal Danish Naval Academy. In 1935, he married Princess Ingrid of Sweden. They had three daughters: Margrethe, Benedikte and Anne-Marie. During Nazi Germany's occupation of Denmark, Frederik acted as regent on behalf of his father from 1942 until 1943.

Emperor Ruizong of Tang (22 June 662 – 13 July 716), personal name Li Dan, also known at times during his life as Li Xulun, Li Lun, Wu Lun, and Wu Dan, was the fifth and ninth emperor of the Chinese Tang dynasty. He was the eighth son of Emperor Gaozong and the fourth son of Emperor Gaozong's second wife Empress Wu. He was wholly a figurehead during his first reign when he was controlled by his mother, and he was the titular and puppet ruler of the Tang Empire from 684 to 690. During his second reign after his mother's death, significant power and influence was exercised by his sister Princess Taiping.

In February 684, Li Dan's mother Empress Wu demoted his older brother Emperor Zhongzong (Li Xian) who had attempted to rule free of his mother and named him emperor (as Emperor Ruizong). Emperor Ruizong, however, was a hollow figurehead under control of his mother and had no real power, even nominally, his name was not included in the issued documents or orders. He was not even able to move freely around his private residence, let alone attend to governmental affairs. From then onwards, the Tang dynasty existed only in name and Empress Dowager Wu ruled China for over six years as quasi-emperor. Empress Wu, was comfortable about the empire being entirely under her control, decided finally to seize the throne, so in October 690 Emperor Ruizong ceded the imperial throne to his mother, who installed herself as empress regnant – the only woman in Chinese history ever to rule with this title. She issued a decree that ended the Tang dynasty and founded the Zhou dynasty. Emperor Ruizong was reduced to the position of crown prince, with the unconventional title of Huangsi (皇嗣, "imperial successor"). In the following years, Empress Wu's nephews Wu Chengsi and Wu Sansi tried to have one of them named heir to the throne, but Wu Zetian resisted these calls. Eventually, in October 698, faced with foreign invasion and dissatisfaction at home, Empress Wu accepted the suggestion of the chancellor Di Renjie and recalled the exiled Li Xian to the capital Luoyang. Soon, Li Dan offered to yield the position of crown prince to his elder brother, and Li Xian became crown prince instead.

Emperor Yang of Sui (Chinese: 隋煬帝, 569 – 11 April 618), personal name Yang Guang (楊廣), alternative name Ying (英), childhood name Amo (阿摩), Xianbei name Puliuru Guang (普六茹廣), was the second emperor of the Sui dynasty of China.

Emperor Yang's original name was Yang Ying, but he was renamed by his father Emperor Wen, after consulting with oracles, to Yang Guang. Yang Guang was made the Prince of Jin after Emperor Wen established the Sui dynasty in 581. In 588, he was granted command of the five armies that invaded the Chen dynasty in southern China and was widely praised for the success of this campaign. These military achievements, as well as his machinations against his older brother Yang Yong, led to him becoming crown prince in 600. After the death of his father in 604, generally considered, though unproven, by most traditional historians to be a murder ordered by Yang Guang, he ascended the Sui throne.

Emperor Taizong of Tang (28 January 598 – 10 July 649), previously Prince of Qin, personal name Li Shimin, was the second emperor of the Tang dynasty of China, ruling from 626 to 649. He is traditionally regarded as a co-founder of the dynasty for his role in encouraging his father Li Yuan (Emperor Gaozu) to rebel against the Sui dynasty at Jinyang in 617. Taizong subsequently played a pivotal role in defeating several of the dynasty's most dangerous opponents and solidifying its rule over China proper.

Taizong is considered to be one of the greatest emperors in China's history, and henceforth his reign became regarded as the exemplary model for which all future emperors were measured. His era, the "Reign of Zhenguan" (Chinese: 貞觀之治; pinyin: Zhēnguàn Zhī Zhì) is considered a golden age in ancient Chinese history and was treated as required studying material for future crown princes. Taizong continued to develop imperial examination systems. He asked his officials to be loyal to policies, not people, in order to eliminate corruption. Under the Zhenguan era, Tang China flourished economically and militarily. For more than a century after his death, China enjoyed prosperity and peace brought about by the solidification of imperial protection over the Chinese regions. In territorial extent, it covered most of the territories previously held by the Han dynasty as well as parts of modern-day Korea, Vietnam, Russia, Mongolia, Xinjiang, and Central Asia. This era of consolidation and conquest laid the foundation for Xuanzong's reign, which is considered to be the height of the Tang dynasty.

Amenhotep I (/ˌæmɛnˈhoʊtɛp/) or Amenophis I (/əˈmɛnoʊfɪs/ from Ancient Greek Ἀμένωφις), was the second Pharaoh of the 18th Dynasty of Egypt. His reign is generally dated from 1526 to 1506 BC (Low Chronology).

He was a son of Ahmose I and Ahmose-Nefertari but had an elder brother, Ahmose-ankh, and was not expected to inherit the throne. However, sometime in the eight years between Ahmose I's 17th regnal year and his death, his heir apparent died and Amenhotep became crown prince. He then acceded to the throne and ruled for about 21 years.

Taizi (Chinese: 太子; pinyin: tàizǐ; lit. 'Supreme Son') was the title of the crown prince of imperial China.

Usermaatre Heqamaatre Setepenamun Ramesses IV (also written Ramses or Rameses) was the third pharaoh of the Twentieth Dynasty of the New Kingdom of Ancient Egypt. He was the second son of Ramesses III and became crown prince when his elder brother Amenherkhepshef died aged 15 in 1164 BC, when Ramesses was only 12 years old. His promotion to crown prince is suggested by his appearance (suitably entitled) in a scene of the festival of Min at the Ramesses III temple at Karnak, which may have been completed by Year 22 [of his father's reign]. (the date is mentioned in the poem inscribed there)

As his father's chosen successor, the prince employed three distinctive titles: "Hereditary Prince", "Royal scribe" and "Generalissimo." The latter two titles are mentioned in a text at the temple of Amenhotep III at Soleb and all three titles appear on a lintel now in Florence, Italy. As heir-apparent he took on increasing responsibilities; for instance, in Year 27 of his father's reign, he is depicted appointing a certain Amenemope to the important position of Third Prophet of Amun in the latter's TT 148 tomb. Amenemope's Theban tomb also accords prince Ramesses all three of his aforementioned sets of royal titles. Despite the 31-year reign of his father Ramesses III, Ramesses IV was only 21 when he became pharaoh, and only reigned for six and a half years. His rule has been dated to 1155 to 1149 BC.

Wali al-Ahd (Arabic: ولي العهد, romanized: Walī al-ʿAhd) is the Arabic and Islamic term for a designated heir of a ruler, or crown prince.