Maria I (Portuguese: Maria I de Portugal; 17 December 1734 – 20 March 1816) was Queen of Portugal, Brazil, and the Algarves. Known as Maria the Pious (in Portugal), or Maria the Mad (in Brazil), she was the first undisputed Queen regnant of Portugal and the first monarch of Brazil. Maria was born at the Ribeira Palace in Lisbon. On the day of her birth, her grandfather, King John V of Portugal, created her the Princess of Beira. When her father succeeded to the throne in 1750 as Joseph I, Maria, at age 16 and as his eldest child, became his heiress presumptive and was given the traditional titles of Princess of Brazil and Duchess of Braganza. In 1777, Maria became the first undisputed queen regnant of Portugal and the Algarves. With Maria's accession, her husband became king as Peter III.

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