After the city was designated as the seat of a bishop by Pope Paul III in 1545, the military architect Afonso Álvares, who is probably also responsible for the cathedral in Portalegre, was commissioned in 1550 to build a new cathedral. Slightly modified by later renovations, it was badly damaged in the Lisbon earthquake (1755). Although the church was consecrated in 1774, it was still unfinished when the architect died. During the Napoleonic Wars on the Iberian Peninsula, marauding soldiers destroyed the entire interior in 1811.