Dom John VI (Portuguese: João VI;[2][3] 13 May 1767 – 10 March 1826), nicknamed "the Clement", was King of the United Kingdom of Portugal, Brazil and the Algarves from 1816 to 1825. Although the United Kingdom of Portugal ceased to exist de facto beginning in 1822, he remained its monarch de jure between 1822 and 1825. After the recognition of the independence of Brazil under the Treaty of Rio de Janeiro of 1825, he continued as King of Portugal until his death in 1826. Under the same treaty, he also became titular Emperor of Brazil for life, while his son, Emperor Pedro I, was both de facto and de jure the monarch of the newly independent country.
John VI was born in Lisbon in 1767 during the reign of his maternal grandfather, King Dom Joseph I of Portugal. He was the second son of the Princess of Brazil and Infante Peter of Portugal, who later became Queen Dona Maria I and King Dom Peter III. John became heir to the throne when his older brother, Prince José, died of smallpox in 1788 at the age of 27. Before his accession to the Portuguese throne, John bore the titles Duke of Braganza, Duke of Beja, and Prince of Brazil. From 1799, he served as prince regent due to the mental illness of his mother. In 1816, he succeeded his mother as monarch of the Portuguese Empire, with no real change in his authority, since he already possessed absolute powers as regent.
One of the last representatives of absolute monarchy in Europe, John VI lived during a turbulent period; his reign never saw a lasting peace. Throughout his period of rule, major powers, such as Spain, France. and Great Britain, continually intervened in Portuguese affairs. Forced to flee across the Atlantic Ocean to Brazil when troops of the Emperor Napoleon I invaded Portugal, he found himself faced there with liberal revolts; he was compelled to return to Europe amid new conflicts. His marriage was no less conflictual, as his wife Carlota Joaquina of Spain repeatedly conspired against her husband in favor of personal interests or those of her native Spain.
John lost Brazil when his son Pedro declared independence, and his other son Miguel (later Miguel I of Portugal) led a rebellion that sought to depose him. According to recent scholarly research, his death may well have been caused by arsenic poisoning. Notwithstanding these tribulations John left a lasting mark, especially in Brazil, where he helped to create numerous institutions and services that laid a foundation for national autonomy, and many historians consider him to be a true mastermind of the modern Brazilian state. John's contemporaries viewed him as a kind and benevolent king, although later generations of Portuguese and Brazilians have made him the subject of frequent caricature. However, in recent decades his reputation has been restored as a clever king who was able to balance many competing interests.