Maria I, Queen of Portugal was the daughter of Dom Jose Manuel. She married her father's younger brother, Pedro in 1772 and five years later became Queen of Portugal.

A court clique soon influenced Queen Maria to dismiss the unpopular dictator Pombal (1777) and this faction of grandees was to remain in power for the rest of Maria's reign. Noteworthy events of this period were Portugal's membership of the League of Armed Neutrality (July 1782)and the 1781 cession of Delagoa Bay from Austria to Portugal. In 1801 the Spanish dictator Manuel de Godoy invaded Portugal with backing from Napoleon, but was forced to abandon the campaign in the same year. However the Treaty of Badajoz on June 6 1801 forced Portugal to cede Olivenza and part of Guyana to Spain.

The incurable condition of porphyria made Queen Maria incapable of handling state affairs after 1799 and so her son Prince John became regent. The refusal of his government to join the Continental Blockade of Britain culminated in the 1807 Franco-Spanish invasion led by Marshal Junot. The Braganza dynasty fled to Brazil on November 13, 1807, and Junot was appointed governer of the kingdom pending Napoleon's decision on its ultimate fate. On August 1, 1808, the British General Arthur Wellesley (later Duke of Wellington) landed a British army in Lisbon and thus commenced the Peninsular War. Wellesley's initial victory over Junot at Vimeiro (August 21 1808) was wiped out by his superiors in the Convention of Cintra (August 30). Nevertheless Wellesley (now Lord Wellington) returned to Portugal on April 22, 1809 to recommence the campaign. Portuguese forces under British command distinguished themselves in the defence of the Torres Vedras lines (1809-1810) and in the subsequent invasion of France. When Napoleon was finally defeated in 1815, Maria and her family were still in Brazil. The aged Queen died at Rio de Janeiro in January 1816 and the Prince Regent succeeded her as King John VI of Portugal and Brazil.

Preceded by:
D. José Manuel
List of Portuguese monarchs
List of Brazilian monarchs
Succeeded by:
Joćo VI