Haile Selassie, served his country, Ethiopia, as its regent from 1916 to 1930 and as its emperor from 1930 to 1974. He introduced the first Ethiopian constitution, abolished slavery, chaired the Organisation of African Unity, and helped Ethiopia enter the UN. He inspired the Rastafari movement, too.
3 George V
George V became the King of Great Britain and the British Dominions in 1910. During the World War I, he played an active role in supporting the troops. The rise of socialism, communism, fascism and the Indian independence movement was witnessed during his rule. His reign also saw the supremacy of the elected British House of Commons established by the Parliament.
Emperor Meiji of Japan presided over the all-round revolutionary transformation of his empire which emerged as a strong force on the global scene during his reign. His policies and actions led to Japan’s rapid growth and ended its isolation from the rest of the world. One of the noted changes during rule was the abolition of special privileges of samurais.
George I of Greece reigned as the king of Greece from 1863 until his murder in 1913. During his reign of nearly 50 years, which is the longest in the history of modern Greece, George helped expand Greece's territory significantly. During his reign, Greece also became increasingly prosperous and attained a popular place on the European stage.
Bhumibol Adulyadej of the Chakri dynasty reigned as the ninth monarch of Thailand. Reigning from 1946 until his death in 2016, Adulyadej is the second-longest reigning monarch in the history. During his reign, Bhumibol Adulyadej retained enormous constitutional powers and was extremely popular among his subjects, with some even seeing him as close to divine.
Mohammad Reza Pahlavi served as the last king of Iran from 1941 to 1979. During his reign, Iran witnessed rapid military and industrial modernization and several social and economic reforms. During his rule, Iran also enjoyed a spike in economic growth, surpassing France, England, and the US. However, the Iranian Revolution, which was unusual in many ways, overthrew the king.
King Hussein of Jordan reigned as the king of Jordan from 1952 to 1999. As a royal member of the House of Hashim, Hussein was a direct descendant of Prophet Muhammad. At the time of Hussein's accession, Jordan was a young nation with few natural resources. However, by the end of his reign, Jordan had become a stable, modern state.
Puyi served as the final emperor of China's last imperial dynasty, The Qing dynasty. After Manchuria was invaded by Japan, Puyi became a puppet at the hands of the Japanese and was chosen as the emperor of the puppet state of Manchukuo. He then signed many edicts, given to him by the Japanese, including the one that made slavery legal.
Olav V of Norway served as the king of Norway from 1957 to 1991. Olav became heir apparent to the throne in 1905 when his father was crowned king of Norway. His leadership skills during World War II earned him the position of Norwegian Chief of Defence in 1944. Nicknamed The People's King, Olav was popular for his down-to-earth style.
Emperor Taishō was the 123rd Emperor of Japan. He was the son of Emperor Meiji and Yanagihara Naruko, a concubine. As the eldest living son of the emperor, he was formally named the crown prince in 1888. Upon the death of his father in 1912, he ascended the throne. A sickly man with disabilities, he died at 47.
Faisal of Saudi Arabia was King of Saudi Arabia from 1964 to 1975. He was the son of King Abdulaziz and his wife, Tarfa. During his father’s reign, he was given numerous responsibilities of political significance. After coming to power, he implemented a series of modern reforms and issued a decree for the total abolition of slavery.
Christian IX of Denmark was King of Denmark from 1863 to 1906, having claimed the throne following the death of King Frederick VII. During his early reign, the Danish saw defeat in the Second Schleswig War and lost several duchies. Recovering from a tumultuous start, he reigned over his nation for several years and was respected by his people.
Jigme Khesar Namgyel Wangchuck is Druk Gyalpo or "Dragon King" of the Kingdom of Bhutan. He is the son of Jigme Singye Wangchuck, who abdicated the throne in his favor in 2006. As the king, he began overseeing the democratization of Bhutan and has implemented several reforms to improve the standard of living in his country.
23 Mehmed VI
Mehmed VI was the last Sultan of the famous Ottoman Empire. He reigned from 1918 to 1922 before the empire was dissolved, making way for the creation of the Republic of Turkey. Apart from ruling the Ottoman Empire, Mehmed VI also enjoyed music, calligraphy, and writing poems. In 1922, he stepped down, enabling the abolition of the Ottoman Sultanate.
Albert I of Belgium ruled as King of the Belgians for over 25 years from 1909 to 1934. He played a crucial role during World War I, for which he is often referred to as the Soldier King or Knight King in Belgium. A renowned alpinist, Albert died in a mountaineering accident and his death was mourned around the world.
Umberto II, the only son of King Victor Emmanuel III, was the last king of Italy and ruled for just 34 days, from May 9 to June 12, 1946, and then went into exile. Also known as Re di Maggio, he was the de facto head of state since 1944.
30 Mehmed V
Mehmed V was the 35th and penultimate Ottoman Sultan who reigned from 1909 to 1918. One of the sons of Sultan Abdulmejid I, he succeeded his brother Abdul Hamid II after the Young Turk revolution. His reign was marked by the loss of the empire’s many territories and witnessed the Ottoman Empire’s entry into World War I.
Chulalongkorn reigned as the king of Siam from 1868 until his death in 1910. Nicknamed the Royal Buddha, Chulalongkorn's reign witnessed the modernization of Siam; several social and governmental reforms marked his reign. Since the reforms ensured Siam's survival despite Western colonialism, Chulalongkorn earned the title, the Great Beloved King.
Belgian king Leopold III was despised by his countrymen for surrendering Belgium to the Germans during World War II. After being imprisoned by the Germans near Brussels, he went to Austria, and went back to Belgium later, only to be faced by a civil war that forced him to abdicate.
33 Christian X
Alexander I of Yugoslavia reigned as the king of Yugoslavia from 1921 until his death in 1934. During a state visit to France, Alexander was murdered by Bulgarian Vlado Chernozemski. The assassination inspired the opening of Christopher Hyde's book, The Second Assassin. Alexander's life and career inspired a TV series titled Alexander of Yugoslavia.
Frederick IX of Denmark reigned as the king of Denmark from 1947 until his death in 1972. Under his reign, the Danish society experienced a rapid change; the economy received a massive boost in the 1960s which allowed women to enter the labor market. In 1982, Frederick's statue was unveiled in Copenhagen, ten years after his death.
Norodom Sihamoni has had an interesting childhood, from studying in Czechoslovakia to joining a film school in North Korea, to moving to China after the fall of Pol Pot. A skilled choreographer who had his own dance troupe in Paris, he later rather reluctantly became the king of Cambodia.
George II of Greece was the King of Greece for two terms, from 1922 to 1924 and from 1935 to 1947. He was the eldest son of King Constantine I and his wife, Sophia of Prussia. He reigned during a tumultuous time in Greek history. Upon his death, he was succeeded by his younger brother, Paul.
41 Edward VII
Edward VII, the King of the United Kingdom of Great Britain and Ireland and Emperor of India from 22 January 1901 until his death, is said to have played a role in the reorganisation of the British Army after the Second Boer War. His main interests lay in the fields of foreign affairs and naval and military matters.
Paul of Greece served as the King of Greece from 1947 to 1964. Before succeeding to the throne, Paul trained as an army officer and then worked in an aircraft factory. As the king, he helped rebuild Greece's diplomatic and trade links after the end of the Greek Civil War.
Carol II of Romania reigned as king of Romania from 1930 to 1940. He played a major role in establishing a royal dictatorship in Romania by abolishing the political parties and removing the 1923 constitution. He replaced the political parties with the National Renaissance Front, a single monopoly party of government.
48 Sobhuza II
Sobhuza II was the king of Swaziland from 1899 to 1982, although his coronation took place in 1921 as he was too young to rule early in his reign. His reign of 82 years and 254 days makes him the longest-reigning monarch in recorded history. Sobhuza II played a key role in events that eventually led to his country's independence.
Carl XVI Gustaf of Sweden has been serving as the king of Sweden since the demise of his grandfather King Gustaf VI Adolf in 1973. He is currently the longest-reigning monarch in the history of Sweden. Apart from being passionate about the environment, agriculture, technology, and trade, the king is also fond of automobiles and owns many Porsche 911s.