Originally constructed in 1598, São Bento has served as the seat of Portugal's parliament since 1834, when the former monastery of the Benedictine Order was dissolved after the Liberal Wars.

[1] The Chapter house (meeting place of the monks) of the monastery was totally remodeled by French architect Jean François Colson into a session room in 1867.

Ventura Terra built a new session room for the lower house (inaugurated in 1903) and altered the facade of the building, adding a neoclassical portico with columns and a triangular pediment.

Since Portugal became a democracy after the 1974 Carnation Revolution the area in front of the palace has been the most popular location for demonstrations held in Lisbon.

This modern structure was designed by Fernando Távora[1] and allowed for an expansion of the space of the Portuguese Assembly without altering its historical outlook.