With the transfer of the seat of the Bishopric of Egitânea (Idanha-a-velha) to Guarda in 1203, under the influence of King Sancho I, it was necessary to promote the construction of a Cathedral. If the original building is not known, it is known that the construction of the current Cathedral began in 1390 but, given the scale of the project, the works dragged on and the building was only finished in the Manueline context (beginning of the century XVI). The interior of the Cathedral, of great compositional clarity, has a Gothic design, with the monumental altarpiece in the chevet altar, carved in ançã stone and attributed to the school of João de Ruão, representing episodes from the Life of Christ, worthy of mention. The constructive and aesthetic qualities of the Sé Cathedral make it one of the greatest monuments in the entire history of Portuguese architecture.