Archaeological vestiges dating from the Bronze Age suggest that a castro existed on the site. Specifically, the archaeologists identified a pistiliforme sword, dating the late
Bronze Age, found on the locale (but later transferred to the
Museum of Guarda). Castelo Bom was part of an area of disputed lands between Portugal and the
Kingdom of León between the 12th and 13th century. During this period, Castelo Bom was in the advance guard against León, resulting in its early medieval plan. During the 12th century, it was occupied and operated by the León, but the settlement was conquered in 1282 by Portuguese King D.
Dinis, who immediately ordered it structural reinforcement. The same king conceded to the region a
Foral (
charter) in 1296, and it was integrated in to the Kingdom of Portugal as a result of the Treaty of Alcanices. Between the 13th and 14 century, the castle was reconstructed, along with the wall fortifications. By 1496, the formal institutional
Inquirição (
Inquiries), noted the existence of a population of 234. In the 16th century, Francisco de Anzinho and Garcia Fernandes worked at the castle to refortify the installation. Designs by
Duarte de Armas, in his
Book of Fortresses (1509) for the castle drew the castle annexed to the southern extremity of the town walls. These drawings included the castle and barbican, both of an irregular plan. The castle was crowned by
merlons and encircled by adarve, but with a western rectangular tower keep (covered in tiled roof) backed up to a central courtyard, earthen works, a cistern, a shaded house and other dependencies. In the east, is a similar rectangular tower with "dungeon" and in the north, a rectangular tower beside the gate: both towers were in states of ruin. The
barbican, with adarve, merlons and cruciform slits, included a circular tower in the south and minor rectangular tower in the north, flanked by a door (and a complimentary false door in the east). The fortifications consisted of a double line of walls with steps in the west and doors: rectangular doors to the exterior and rounded doors to the interior. The interior doors were surmounted by covered balcony with
machicolations. Both lines of walls included
Chemin de rondes and crowned by
parallelepiped and pyramidal merlons in the northeast, over a rectangular tower covered in partially-ruined pyramidal merlons facing the interior. Within the walls the
urban agglomeration consisted of single-family homes overlooking a church with bell-tower in the south, while in the southwest and southeast were smaller chapels. To the south, the castle was in viewing distance of the
castles of Almeida and
Castelo Rodrigo. In 1510, King D.
Manuel I renewed the foral, and ordered the repair of the castle and fortifications. But, these works did not begin until 1512, under the direction of João Ortega, from Penamacor, and mason Pero Fernandes, with overseer Rui de Andrade, who was discharged by the King. The medieval
Numeramento, carried out in 1527, identified a population of just under 396. In the 17th century, the
Viscount of Vila Nova de Cerveira and Marquesses of
Ponte de Lima, was appointed alcalde-mor, who installed two artillery-pieces and constructed a
bastion tower with vaulted space occupied by a jail. During the
Restoration Wars, it was an important frontier defense and served as a shelter for the governors of Beira, when the cisterns (the
Poços de El-Re and
Poços da Escada). It was mentioned in the 1758
Memórias Paroquiais. The town and castle began its progressive decline in 1762, when the town was encircled and overrun. J. Almeida referred to the existence of watchtower in the
Cabeço da Medronheira, dating to the 18th century, but where no vestiges exist. By the second decade of the 19th century, the French invasion of the peninsula resulted in the destruction of the castle, and the revision of the administrative authority resulted in the extinction of the municipality of Castelo Bom (in 1834). The castle's defensive structures progressively fell into ruin. By the 1950s, the keep tower remained intact, but the descendant of its original owners wanted to construct a court for donkeys (F. Keil do Amaral). The castle was already in ruin and partially buried by 1987, when a study was elaborated by the
Direcção Geral dos Edifícios e Monumentos Nacionais (DGMEN) in order to recuperate the urban centre and the castle architecture. Work on the site began, innocuously with the clearing of the village gate in the 1940s, but proceeded to more elaborate consolidation of the cistern and the area around the resource by 1966. In order to attract more tourists to the site, an overlook was constructed in 1999 (in the north). Work to rehabilitate the facades of the historic centre were initiated at the same time, as part of the
Aldeias Preservadas project, between the local government and the building's property-owners. == Architecture ==