The beginnings of the Nossa Senhora da Oliveira Church date back to the monastery dedicated to the Saviour of the World, the Blessed Virgin Mary and the Holy Apostles, which was founded at this location by the Countess Mumadona Dias in the year 949 AD. Little remains of the original construction although a Romanesque chancel dating from the second half of the twelfth century and originating from the main church portal is preserved in the Alberto Sampaio Museum.
The arches of the cloister and the portal of the Chapter Hall, a work of excellent constructive technique, are testimony to Portugal's finest Romanesque-Mudéjar ensemble.
The invocation of Our Lady of Oliveira arose after 1342, with the greening of an olive tree in the border square, although the area was already an important pilgrimage hub to venerate an image of Santa Maria - the same one that was worshipped by D. João I on the eve of the Battle of Aljubarrota. Having won the battle, and in fulfilment of the King’s promise, the building was remodelled. Work continued until at least 1413, becoming a landmark of Gothic architecture in northern Portugal. The large window in the upper half of the main facade is integrally dedicated to the genealogy of the Virgin. In the altarpiece of the main chapel is an ancient image of Our Lady of Oliveira.
The building also includes Manueline elements, especially the bell tower, which was rebuilt by the Prior D. Diogo Pinheiro in 1513, and in which is the Burial Chapel of his parents. At the end of the 17th century, King Peter II ordered the main chapel to be enlarged, his coat of arms can be seen in the vault; from the same period is the 17th-century chancel with neoclassical backrests, another of the monument’s highlights, along with the altarpiece of the High Altar (dating from the second half of the 18th century), the silver altar of the Chapel of the Blessed Sacrament, and the large baroque canvases, attributed to Pedro Alexandrino, that adorn the walls. The building underwent modifications in the 19th and 20th centuries.In 1801, against the will of the population, the local council dug up an olive tree that had for years occupied the space in front of the church.
References:The Church of St Donatus name refers to Donatus of Zadar, who began construction on this church in the 9th century and ended it on the northeastern part of the Roman forum. It is the largest Pre-Romanesque building in Croatia.
The beginning of the building of the church was placed to the second half of the 8th century, and it is supposed to have been completed in the 9th century. The Zadar bishop and diplomat Donat (8th and 9th centuries) is credited with the building of the church. He led the representations of the Dalmatian cities to Constantinople and Charles the Great, which is why this church bears slight resemblance to Charlemagne's court chapels, especially the one in Aachen, and also to the Basilica of San Vitale in Ravenna. It belongs to the Pre-Romanesque architectural period.
The circular church, formerly domed, is 27 m high and is characterised by simplicity and technical primitivism.