 Complete the following phrase:  The Palace of Queluz ,  is an 18th-century palace located at Queluz, a city of the Sintra Municipality, in the Lisbon District, on the Portuguese Riviera. One of the last great Rococo buildings to be designed in Europe, the palace was conceived as a summer retreat for Dom Pedro of Braganza, later to become husband and then king consort to his own niece, Queen Maria I. It served as a discreet place of incarceration for Queen Maria as her descent into madness continued in the years following Dom Pedros death in 1786. Following the destruction by fire of the Ajuda Palace in 1794, Queluz Palace became the official residence of the Portuguese prince regent John VI, and his family and remained so until the royal family fled to the Portuguese colony of Brazil in 1807 following the French 