"This is the largest of the reception halls in the Palace, built around 1770. During the time of Pedro III and Maria I, this was where great parties and receptions were held." (parquesdesintra.pt)
Born in 1734, Maria was a daughter of King Joseph (1714-1777), during whose reign much of Lisbon was destroyed by the great earthquake of 1755. In 1760, Maria married her uncle--her father's younger brother. In 1777, when she became Queen Maria I, her husband became king consort, Pedro III (1717-1786). Maria died in Brazil in 1816. (Britannica)