Rama III (Nangklao) Chakri

Chulalongkorn, known as Rama V, reigned as King of Siam from 1868 to 1910 and is regarded as one of the country's greatest modernizing monarchs. Born in 1853, the son of Rama IV and Queen Debsirindra, he abolished slavery and the prostration custom, reformed the civil service, judiciary, and tax system along Western lines, and built Siam's first railways and telegraph network, all while skillfully navigating British and French colonial pressure to keep the kingdom the only Southeast Asian state never colonized. With his consort Queen Saovabha Phongsri he had several sons who later reigned as kings, including Vajiravudh (Rama VI), Prajadhipok (Rama VII), and, through his son Prince Mahidol, grandsons Ananda Mahidol (Rama VIII) and Bhumibol Adulyadej (Rama IX). He died in 1910.

Vajiravudh, known as Rama VI, reigned as King of Siam from 1910 to 1925. Born in 1880, the son of Rama V and Queen Saovabha Phongsri, he was educated in Britain and became a prolific writer and translator, introducing Western drama and modern Thai literature to the court. He introduced the use of surnames in Siam, established the Wild Tiger Corps paramilitary organization, and brought Siam into the First World War on the Allied side in 1917. He had no son; a daughter was born to him only days before his death in 1925, so the throne passed to his younger brother, Prajadhipok, who became Rama VII.

Prince Mahidol Adulyadej was a son of King Rama V and Queen Saovabha Phongsri, and the father of two future kings, Ananda Mahidol (Rama VIII) and Bhumibol Adulyadej (Rama IX). Born in 1892, he studied public health and medicine at Harvard University in the United States, and is honored in Thailand as the father of modern medicine and public health for his work establishing medical education and hospital standards. He married Sangwan Talapat, later titled Srinagarindra, and the couple had three children. He died in 1929, well before either of his sons came to the throne, and never reigned himself.

Prajadhipok, known as Rama VII, reigned as King of Siam from 1925 to 1935 and was the last absolute monarch of the Chakri dynasty. Born in 1893, the youngest son of Rama V and Queen Saovabha Phongsri, he came to the throne unexpectedly after his brother Rama VI died without a surviving son. His reign was transformed by the bloodless Siamese revolution of 1932, which ended absolute monarchy and established a constitutional system; he initially cooperated with the new government but, after political disputes over his powers, abdicated the throne in 1935 while in England, where he remained until his death in 1941. He married Queen Rambhai Barni and had no children.

Ananda Mahidol, known as Rama VIII, was King of Thailand from 1935 to 1946. Born in Heidelberg, Germany in 1925, the elder son of Prince Mahidol Adulyadej and Srinagarindra, he was still a schoolboy in Switzerland when he inherited the throne at age nine following his uncle Prajadhipok's abdication, and a regency governed in his name for most of his reign. He returned to Thailand only briefly as an adult before his sudden death at the Grand Palace in Bangkok in June 1946, at age twenty. He was succeeded by his younger brother, Bhumibol Adulyadej, as Rama IX.

Bhumibol Adulyadej, known as Rama IX, reigned as King of Thailand from 1946 until his death in 2016, the longest reign of any Thai monarch. Born in Cambridge, Massachusetts in 1927, the younger son of Prince Mahidol Adulyadej and Srinagarindra, he succeeded his elder brother Ananda Mahidol at age eighteen. Over seven decades he became a unifying figure through repeated political upheavals, sponsoring thousands of rural development projects on poverty, agriculture, and water management. He married Sirikit in 1950, and their four children were Ubolratana, Vajiralongkorn (later Rama X), Sirindhorn, and Chulabhorn. He died in Bangkok in 2016.

Princess Ubolratana Rajakanya is the eldest child of King Bhumibol Adulyadej and Queen Sirikit, and the elder sister of King Vajiralongkorn (Rama X). Born in Lausanne, Switzerland in 1951, she gave up her royal titles in 1972 upon marrying an American, Peter Ladd Jensen, and lived in the United States for over two decades, working as an actress and businesswoman. Following her divorce, she returned to live in Thailand in the early 2000s and resumed an active public role in royal family events, though without reinstating her full royal title. She has remained largely engaged in charitable and film-related work.

Maha Vajiralongkorn, known as Rama X, has reigned as King of Thailand since 2016, succeeding his father Bhumibol Adulyadej. Born in Bangkok in 1952, the only son of Bhumibol and Queen Sirikit, he was educated in Australia and the United Kingdom and trained as a military pilot before being formally named Crown Prince in 1972. He assumed the throne after a period of mourning following his father's death, and was formally crowned in a traditional ceremony in 2019. He has been married several times; his current wife, since 2019, is Queen Suthida. He is the tenth monarch of the Chakri dynasty.

Princess Maha Chakri Sirindhorn is the second daughter of King Bhumibol Adulyadej and Queen Sirikit, and a younger sister of King Vajiralongkorn (Rama X). Born in Bangkok in 1955, she pursued advanced academic studies in history, Pali, and Oriental languages, and has long been regarded as one of the most publicly active and popular members of the Thai royal family for her work in education, rural development, and disaster relief. In 1977 she was granted the special title Maha Chakri, elevating her standing among the royal children. She has never married and remains a full-time working member of the royal family.

Somdet Phra Sri Suriyendra (born Boonrod) was the principal queen consort of King Rama II and mother of Prince Mongkut, who later reigned as Rama IV. Born in 1767, she was a cousin of her husband and held the highest rank among his consorts, giving her son a strong claim to the succession that was nonetheless passed over in 1824 in favor of his older half-brother, Rama III. She lived to see Mongkut spend nearly three decades as a Buddhist monk before finally ascending the throne in 1851, though she died in 1836, some years before his accession.

Somdet Phra Debsirindra (born Rampoei Sirindhara) was the principal queen consort of King Rama IV (Mongkut) and mother of his successor, Chulalongkorn, later Rama V. Born in 1834, she was a granddaughter of Rama II and thus a member of the royal family in her own right before her marriage. She died in 1861 while Chulalongkorn was still a child, seven years before he came to the throne, and did not live to see her son's reign. She is remembered as the mother of one of Siam's most celebrated modernizing kings.