The Basilica Cathedral of St. Mary of the Assumption is a large Gothic building situated in the Polish city of Włocławek located near to the Vistula River.

In the years 1883–1901, the building was heavily regothicised, including exchange of details and elevation of both towers.

Among the monuments located inside, the following deserve particular attention: stained-glass windows from 1360, the tombstone of bishop Peter of Bnin from 1494, a wooden statue of Our Lady from the early fifteenth century and the painting of the Assumption of the Blessed Virgin Mary by John the Great from around 1480.

According to the chronicler Jan Dlugosz, bishop Swidger (around 1133) equipped the new cathedral in Wloclawek, and adapted the castle chapel which was dedicated to St. Mary of the Assumption.

The waters of the Vistula River, and fires also contributed to its destruction, which finally led to the building of a new cathedral under the guidance of the bishop Michal Godziemba (1222-1252).

On 7 May 1329 Teutonic troops captured Wloclawek, and destroyed the borough, concentrating in particular on the bishop's property.

On 24 August 1330 Maciej of Golancz decided to sign a pact with the Grand Master of the Teutonic Knights, Werner von Orseln, who allowed him to resume public religious activities.

The first stage, including the presbytery, southern vestry and treasury, were most likely completed under the guidance of Maciej Golanczewski.

During Zbylut's incumbency in the diocese the roofs of the lofts and vestry were finished, and the high altar with the figure of the Mother of God was set up.

The chronicler Jan Długosz noted in "Roczniki" the beginning of the construction of the present-day cathedral, initiated by Bishop Maciej Pałuka from Gołańcza, who was to lay the foundation stone on 25 March 1340.

Twenty-two quarters of Gothic stained-glass windows from the presbytery have been preserved to this day, currently displayed in the Chapel of St. Barbara.

There are mentions that prelates and canons of the chapter in Wloclawek gave up part of their income for the further building and conservation of the cathedral.

At the beginning of the 16th century these two chapels were remodelled in the Mannerist style which included covering them with cupolas with lanterns.

The bishop Wincenty Teofil Chosciak wanted the cathedral to look more monumental and decided to enlarge the towers.

According to his design, a chapel was added along the northern nave as well as the western porch, thus obtaining a symmetrical arrangement of the building.

The towers, originally not higher than the roof of the main nave, and later covered with bubble domes, were extended by two soaring floors in neo-Gothic style.

The works also consisted of replacing numerous elements of decoration of the interior, which obliterated the original Gothic character of the cathedral.

The monument was transferred to Włocławek during World War II together with a group of German settlers from Latvia, who were resettled as part of the Heim ins Reich action.

The cathedral contains some great pieces of art from different centuries, including the following: In 2015 Michal Krygier became the new parish priest.