According to several historical studies, all indicates that the Lisboa Cathedral (Sé, in Portuguese) was built over an old Muslim mosque.
This Cathedral started to be built in 1147, when the city of Lisboa was reconquested from the Moors, by the first king of Portugal, Dom Afonso Henriques.
The project had an identical plan adopted from the Coimbra Cathedral, in accordance with the Romanesque style of that time. However, the plan suffered several alterations, mostly in the Gothic style, on the following centuries with the construction of the Bartolomeu Joanes (on the North side), the irregularly shaped Cloister and the new Deambulatory which construction was ordered by the King Afonso the 4th to act as his family pantheon.
During the Modern Times the building was object of architectural and artistic enrichments such as the Sacristy from the half 17th century, and in the 17th and 18th centuries alterations were made in the baroque style, especially affecting the decoration of the altars and chancel. Nevertheless, most of the works were done in the beginning of the 20th century, with the purpose to restore the primary medieval atmosphere of the Cathedral.
Some archaeological excavations in the Cloisters revealed Roman vestiges and other human presences in this area.
On the left side of the main entrance there is a Franciscan chapel with the sink where Saint Anthony was baptized in 1195, and it is decorated with glazed tiles representing the Saint preaching to the fishes.
In the adjacent chapel there is an amazing a baroque Crib made of cork, wood and terracotta, a masterpiece from Machado de Castro.
The treasure of the Cathedral is situated in the top of the stairways, on the right side. It shelters a diversified collection of silver, ecclesiastical suits, statues, manuscripts, and relics associated to São Vicente. The most precious piece of the cathedral is the chest that contents the mortal remains of the Saint, transferred from the São Vicente Cape, in the Algarve, to Lisboa in 1173. The legend says that two sacred crows kept a permanent vigil on the boat that transported the relics. The crows and the boat became the symbol of the city of Lisboa. In fact, it is said that the descendants of the two original crows lived in cloisters of the cathedral for many years, and probably their own descendents still do.