|This was the first monastery of the Cistercian Order to be founded on Portuguese territory in the 12th century, on a site that had a longstanding monastic tradition. This is clearly shown by the fact that the monastery itself is dedicated to St. John, since, as a rule, the Cistercians dedicated their abbeys to the Virgin Mary. The countless endowments received (the first of them being made by the first king of Portugal, D. Afonso Henriques), coupled with the efficient management of the resources thus acquired, ensured that the monastery enjoyed great prosperity in the 12th and 13th centuries, possessing a vast estate in the north and centre of the country.
The favourite monastery of the French abbey of Clairvaux, it was the mother-house of various monasteries in the north of Portugal: Fiães, São Pedro das Águias and Santa Maria de Aguiar.
The suppression of the Religious Orders in 1834 led to its being adapted to a parish church.