Between the Roman and Muslim occupations there existed a castle fortification by the name of Arminho on the site.[1] The medieval settlement was founded on a Romanized castro, which was a 2nd century presence conditioned by its position over the Ribeira de Seda, identifiable by milestone encountered in the region, among other vestiges.[2]
In 1160, D. Afonso Henriques conquered the settlement from the Moors.[1][2] The construction of the walls likely began following its conquest, along a frontier which was still influenced skirmishes and battles.[2] Following their defeat, the location was donated to the Knights Templar, but in 1271, Seda was transferred to the Knights of Avis; Friar Simão Soeiro, Master of the Order, received a new foral for its development.[2]
On 18 May 1271, a foral (charter) was conceded to Father Simão, Master of Avis, which was later (30 October 1427) validated by King D. John I and reissued on 1 September 1510, by King D. Manuel I.[1]
In the 1527 "Numeramento", it was the seat of the municipality, during the jurisdiction of the Order of Avis, when there were 184 residents.[1]
The municipality was extinguished in 1836, with the administrative reforms.[1]
In 1970, there was a collapse of part of the walls and corbel of the fortification. As a result, in 1971, the Direcção Geral dos Edifícios e Monumentos Nacionais (DGEMN) began the consolidation of the walls and tower.[1] But, urgent repairs were made in 1978, that included patching of the masonry.[1] To protect the castle from complete ruin, the government classified the castle as a Property of Public Interest by decree on 26 February 1982.[1]
Architecture
The castle is located in a rural area, delimited in the east and north by primitive houses.[1] The walls and corbels are situated between the vegetable gardens and yards of the Rua do Castelo, while along the east is an abrupt slope, that is part of a derelict farm.[1]
Of the castle, there remains the embattlement walls with three corbels and vestiges of a fourth. The entire structure is based on an irregular plan.[1][2]
The monument is designated as a castle, but, little remains except for the walls.[1][2] Rui de Azevedo who catalogued Seda as a 12th-13th century fortified settlement, indicated that it was not a castle, between 1350 and 1450, from the records of Baquero Moreno.[1][2][3] Documents from Rui de Pina also indicated that the fortifications of Seda were not identified as a castle in the works of King D. Denis.[1]
^ abcdefgCastelo de Seda (restos), IGESPAR – Instituto de Gestão do Património Arquitectónico e Arqueológico (Portuguese Institute of Architectural and Archaeological Heritage), 2006, retrieved 25 May 2016
Grande Enciclopédia Portuguesa e Brasileira (in Portuguese), vol. 28, Lisbon, Portugal
Almeida, João de (1958), Roteiro dos Monumentos Militares Portugueses (in Portuguese), Lisbon, Portugal{{citation}}: CS1 maint: location missing publisher (link)
Nunes, António (1988), O Castelo Estratégico Português e a Estratégia do Castelo em Portugal (in Portuguese), Lisbon, Portugal{{citation}}: CS1 maint: location missing publisher (link)