St. Lambert's Cathedral, Liège (or in full, the Cathedral of Our Lady and St. Lambert; French: Cathédrale Notre-Dame-et-Saint-Lambert) was the cathedral of Liège, Belgium, until 1794, when its destruction began. This enormous Gothic cathedral, dedicated to Saint Lambert of Maastricht, occupied the site of the present Place Saint-Lambert in the centre of Liège.
Saint Lambert, bishop of Maastricht, was assassinated in Liège about 705, and was initially buried in Maastricht. The site of his martyrdom became a place of pilgrimage, and his successor, Saint Hubert, returned the body and reburied it there. Shortly afterwards, the bishop's seat was transferred from Maastricht to Liège, and Lambert's shrine became a cathedral.
Several structures succeeded each other on the site. The first was a martyr's shrine or mausoleum (martyrium), commissioned by Saint Hubert. Unusually, it was oriented to the west, which may account for the existence of a west choir in later cathedral buildings. Two cathedrals followed. The first, built towards the end of the 8th century, was in Carolingian style.
In 978 Bishop Notger installed a chapter of sixty canons. He then built a new church from around the year 1000, in Ottonian style, with a special crypt for the relics of the martyred saint. The architecture was that of the Holy Roman Empire. The new cathedral had a massive westwork, two choirs at opposite ends, two transepts, each with a tower over the crossing, adding to the monumentality of the structure, and a cloister at the east end. It is noticeable from the groundplan that the entrances were in the north and south sides of the building, and not along the east-west axis. Frederic of Lorriane, later Pope Stephen IX, was canon and archdeacon of this church before being raised to the cardinalate by Pope Victor II.