History of Alvito:
Busy region since the Roman time, of which archaeological vestiges are diverse, the first documentary references are found from the donation of this area, from Alfonso III of Portugal (1248-1279) to his chancellor-mor, Estevão Anes , about 1255 .
Alvito housed the sovereign in 1265, getting, according to custom, the inherent privileges, confirmed for letter-regal. Without heirs, Estevão Anes bequeathed in will to the Order of the Trindade, the town, the castle and the lands of Alvito, what indicates the existence of a structure of previous blockhouse in the place, to the time.
The progress of the village is certified by the institution, in 1296 , of an annual fair.
In 1475 , D. Afonso V (1438-1481) granted the title of baron of Alvito to Fernandes João da Silveira , employee whose descendants would come to be titleholders as marquises. Few years later, in 1482 , the sovereign granted to the baron and its wife the right to construct to a castle, granting to them the landlord of the village and the neighboring towns there.
This nobleman received new confirmations from the license-regal for the construction of the castle, from D. João II (1481-1495), in 1489 , and from D. Manuel I (1495-1521) in 1497 . In accordance with a registration on the entrance gate, the workmanships of the castle would have initiated since 1494 , the time of the 2nd baron of Alvito, D. Diogo Lopes da Silveira . Its workmanships would be concluded in 1504 .
In consequence of the damages the earthquake in 1755 caused, D. Barbarous Maria de Menezes promoted the remodeling and recovery works to it ( 1777 ).
In the end of the century, in 1887 , it was signed a promise of sale of this castle, with clause of fruition until the death, between its owners D. Jose Wolf da Silveira Quaresma and its wife, D. August Carolina Duarte (deceased in 1917 and 1936 ), and future king D. Carlos (1889-1908). Before the death of the old owners, however, the set had been done to the sovereign ( 1897 ).
In century XX , the castle was classified as National Monument for Decree on the 16th June 1910 . After the implantation of the Republic , the former-sovereign D. Manuel II (1908-1910), integrated the castle to the patrimony of the House of Bragança ( 1915 ), in which is stood until today.
In the context of the Cravos Revolution , the dependences of the castle had used by the Commission of the Citizens of Alvito .
Between 1980 and 1981 , new interventions had been executed to the cloth repairing from the wall, coverings, doors, as well as the repairing of the walls of the fence and the nesting of superior doors.
Reconstructed, the dependences of the castle are one of the Pousadas de Portugal , inaugurated in 1993 .
The castle is presented as a building of military architecture and residence, where if they identify Islamic gothic and manuelina influences.
With rectangular plant, its sides define an interior patio where it raises, in the northwest, the Tower of House.
The main door, in beveled arc, exhibits in the superior part, a registration informing that the castle was initiated in the reign of D. João II and finished in D. Manuel I sovereignty. Era served originally for a bridge on the irrigation ditch , acceding itself it the square of weapons where if it detaches, of the south side, a staircase of access to the call Room of the Dee , the Chapel and the rooms of the towers.