The cathedral claims the relics of St Lucius of Britain, said to have been martyred nearby in the late 2nd century.

During the Swiss Reformation, the Catholic population of the city were confined to a ghetto enclosed around the bishop's court beside the cathedral.

The church was completed and consecrated to the Assumption of the Blessed Virgin Mary in 1272 under Bishop Henry of Montfort.

[6] Beginning in the 11th century, the Bishops of Chur began taking sides in secular conflicts as their worldly power grew.

[4] During the conflicts between Frederick Barbarossa and Pope Alexander III following the 1159 papal election, Bishop Egino of Chur sided with the emperor and was rewarded with the dignity of Prince of the Empire (1170).

[7] In 1514 Emperor Maximilian I separated the land surrounding the cathedral from the town of Chur and granted it as an imperial estate to the Bishops.

The bishop fled, and his administrator, Abbot Theodore Schlegel, was publicly beheaded (1 January 1529).

[7] The Ilanz Articles of 1524 restricted the secular power of the bishop to his imperial estate, including the cathedral.

During the Bündner Wirren, the cathedral remained a center of Catholic power in the region.

The interior was completely cleaned, some of the plaster was removed from the walls, the altars were restored and the crypt floor was excavated.

For the rest of the 20th century a museum was added in the crypt and additional repairs, cleaning and renovations continued.

The single bell tower is on the north side of the building between the nave and choir.

This placement allowed for a larger organ without blocking the light from the west window.

It has eight registers which are distributed over two manuals and pedals, but has two preliminaries and a transmission which provide the impression of an eleven-register organ.