This chapel, also known as the Marriage Chapel, is located on the west side of the nave (across from the Bishop's Chapel). This work of art features a wood-carved altarpiece, decorated with gold leaf and framing a painting depicting the Assumption of the Virgin Mary. It was made around 1635 at the Benedictine Abbey in Bellelay, Switzerland by a Spanish monk. When the monks were forced to leave during the religious retaliation, the occupying French troops sold all the precious furniture in the Abbey. At the beginning of the 20th century, the Austrian architect-conservator Rodolphe Messmer discovered the altarpiece in the church of Suarce, France and acquired it. In 1994, Bruno Messmer donated it to the Roman Catholic Archdiocese of Montreal.