Óbidos had its foundation in the existence of a fortified settlement, likely over the Luso-Roman castro[1] and Roman oppidum (then civitas) on the hilltop, that was the mysterious Eburobrittium,[2] once cited by Pliny the Elder as being situated between Collipo (present-day Golpilheira near Leiria) and Olisipo (Lisbon).

[1] This resistance resulted in the epitaph of mui nobre e sempre leal (very noble and ever loyal), that figured into the municipal coat-of-arms.

[1] During the reign of King D. John II (1481–1495), Queen Leonor selected the settlement and castle to reside following the death of her son, the Infante D. Afonso, opting for the thermal waters of the region for treatments necessary during her later life.

[1] During the context of the Peninsular War, the fortification in Óbidos fired the first artillery rounds in the Battle of Roliça (1808) that resulted in the first defeat of Napoleonic forces.

[1] From 1932, the town saw the first interventions of consolidation, reconstruction and restoration by the Direcção-Geral dos Edifícios e Monumentos Nacionais (Directorate-General for National Monuments and Buildings).

The castle and the entire urban area of Óbidos are reclassified as a National Monument by governmental decree published on 5 January 1951.

[1] The spaces were decorated in order to transform it into the Pousada do Castelo, with many of the furniture designed by architects Fernando Augusto Peres de Guimarães andLuís Benavente, with the collaboration made by Leonardo Castro Freire.

[1] The trapezoidal castle oriented to the southeast rises 79 metres (259 ft) above sea level and is situated on the extreme northwest of the walled fortifications.

[1] The perimeter of the walls, reinforced by square and cylindrical plant towers, extends 1,565 metres (5,135 ft) and completely covered by a battlement defended by crenellated parapet.

[1] From here the walls are irregularly adapted to the relief of the land along the northeast, inflecting towards the north and east, and reinforced by semi-circular corbels and the minarets of the castle.

[1] Built by Queen Catherine of Austria, wife of King John III (1521–1557), a 3 kilometres (1.9 mi) aqueduct was constructed to carry water from the mountains of Usseira to Óbidos, supplying the fountains of the town.