At the start of the 13th century, the Prince-Bishop gave some land known as the 'Champs des Maures' to the Cistercian monks, so they could build an abbey.
The monks were tireless builders and worked to clear the land, channel the rivers, drain the marshes and create ponds. Their land also contained coal.
The success of their coal mines, along with generous donations, soon enabled the monks to build a church and monastic buildings.
The buildings were in the Gothic style, arranged around an open cloister. On one side was the church, with the high altar at the east end.
At the end of the Middle Ages, the abbey went through a difficult time, when it was subjected to the fierce flames of two fires, and was pillaged several times.
In the second half of the 16th century, it began to flourish once more and pilgrims came in increasing numbers. In 1629, a large building was added to the abbey in order to accommodate guests: la maison des étrangers.
In the 18th century, Abbot de Harlez demolished the Gothic church and cloister and began the construction of a new abbey.
In 1797, in accordance with Belgian law, religious orders were suppressed and their properties confiscated. The abbey was auctioned on 10 July 1797, only three months after the evacuation of the last Abbot. It was bought by a citizen by the name of Deneef. He destroyed the Abbey Church and transformed the buildings into a flax spinning mill. But the mill was not a success.
A little later, after the fall of the Empire, the prestigious Vonêche glassworks, near Beauraing, found itself in Dutch territory and therefore cut off from the French market. Aimé Gabriel d’Artigues who owned the Vonêche glassworks then bought the Baccarat glassworks in Vosges. Two employees from Vonêche, the chemist François Kemlin and the engineer Auguste Lelièvre, created their own glassworks in the Abbey of Val Saint-Lambert. The location was perfect: the Meuse valley and the highway were close, the buildings were large, and all the raw materials and skilled workers could be found nearby.
From June 1826, smoke rose from the oldest building in the abbey: the first furnace was in operation. The Abbot’s lodgings housed the managers’ office. The east wing - the last remains of the Gothic cloister - was opened up to create an internal railway. From 1835, the glassworks expanded rapidly around the Court du Val courtyard, where around one hundred lodgings were built for workers.