Constructed by the Knights Hospitaller, it is considered both as one of the most important Gothic monuments in Portugal and as the best Portuguese example of a fortress church.

Building of the monastery began around 1340, when the headquarters of the Order of Knights of the Hospital of Saint John of Jerusalem were moved from Leça do Balio near Porto to Crato.

The monastery was made up of three different buildings, a Gothic-style fortress church, a Gothic castle-like palace, and accommodation for the monks.

The church is notable for its height in relation to its narrow nave and wide transept and for the almost-total absence of interior decoration.

The complex acquired its present form in the 1990s when parts were transformed into a hotel of the Pousadas de Portugal chain.