Maria Teresa of Braganza was born in the Royal Palace of Lisbon in April 1793. She was the daughter of Juan VI, King of Portugal, and sister of Maria Francisca of Braganza, the first wife of the Pretender Don Carlos.
1In 1810, she married her cousin Pedro Carlos de Borbón, an admiral in the Portuguese Navy, in Río de Janeiro, with whom she had a son, the Infante Don Sebastian. She was widowed in 1813. She accompanied her sister María Francisca at the Spanish court until they were banished by Ferdinand VII when the dynastic conflict broke out, together with the Infante Don Carlos. They established in Portugal until they had to scape to England harassed by the portuguese liberals.
Her sister Maria Francisca died in September 1834, just as the Pretender joined his troops in the Basque Country. Maria Teresa began to correspond with her brother-in-law from her residence in the Austrian court, where she took charge of the education of her nephews. In February 1838, the two were secretly married by the authorities in Salzburg. After a difficult trip during which she was helped to cross the Pyrenees border by the famed smuggler, Ganix de Macaye, the Princess of Beira met with Don Carlos to ratify their marriage in Azpeitia in October of the same year.
Following the Bergara Convention, Maria Teresa accompanied her husband into exile, first to Bourges and then to Trieste, where he died in 1855.
The Princess of Beira was instrumental in the substitution of Juan III for her son Carlos - Carlos VI for the Carlists - as Pretender, without doubt the most charismatic of the pretenders of this dynasty. After the death of Carlos VI, Count of Montemolín, in 1860, he was succeeded by his brother Juan, which caused a crisis in Carlist lines because the latter was regarded as too liberal by his followers. The Princess of Beira played the role of matriarch of the family, forcing Juan to renounce the throne in favour of her son Carlos, a decision that she certified with her famous "Letter to the Spaniards" of 1864. In this letter, she modernised the concept of legitimacy to justify this change in dynasty.
Maria Teresa of Braganza died in Trieste in January 1874, at the height of the Second Carlist War, while her favourite Carlos VII was fighting for the Spanish throne.