Romanic church built on a pre-Romanic temple. Its initial construction is due to Count D. Henrique de Borgonha, it is therefore prior to the Kingdom of Portugal. It is an important example of the Romanesque style in Portugal, although difficult to decode, due to the varied operations throughout its life.

This Church was built on a pre-Roman temple from the 8th or 9th centuries. In 1100 the church and convent are offered by donation from the Burgundian Count D. Henry to the Benedictine Priory of La Charité-sur-Loire, of the order of Cluny. The Romanesque building was started, gaining greater prominence, in a certain manner in the 12th century, with the support of King D. Afonso Henriques and under the tutelage of the French monks. This is an appreciable example of the Romanesque style of our country, of robust construction, with three naves, a pseudotransept and an interesting collection of sculptural motifs in the arches, portals and capitals. The eardrum has a representation of Christ in Majesty.

According to tradition, Pedro de Rates was one of the first converts by São Tiago in the Iberian Peninsula. In the time of Emperor Caligula, São Tiago had become Pedro as bishop of Braga and a small religious community would have been founded in Rates, where he would suffer martyrdom and receive burial. The current church was built at the initiative of Counts D. Henrique and D. Teresa according to a plan of three naves, five spans and transept. Subsequently, there was a first readjustment towards the model of the Portuguese Benedictine plan for churches with three naves. This transformation will not have been carried out until the end, trying to combine the two plants, which was the basis of numerous anomalies and irregularities sought in the structure of the pillars, in the distribution of the columns along the walls, in the placement of the cracks on the start of the pillars, the application of the buttresses, as well as the lack of uniformity of the elevations.