In the Middle Ages pilgrimages to the grave of Saint Trudo were of great economic significance for the abbey and its surroundings, later the town of Sint-Truiden.
In particular, Wiricus' own apartment, situated on the highest point of the terrain with a panoramic view across the town, was comfortably appointed, with fireplaces and a piped water supply system.
According to the Gesta the walls of the cloisters were covered with polished hardstone panels and groups of columns, either in pairs or in fours, made of black stone and porphyry, with sculpted capitals.
[5] Of the Romanesque conventual buildings and this monument nothing remains, except possibly for some capitals found on the site, probably from the workshop of some stone carver in Liege.
[6] Further building and extensions took place in the 15th and early 16th centuries, during which inter alia Late Gothic points were added to the middle towers of the abbey church.
Finally, at the end of the 18th century, abbot Joseph van Herck had the abbey buildings refurbished in Neo-classical style.
Hubertus van Sutendael (1638–63) built inter alia the still extant Baroque church portal and Nieuwenhoven Castle.
The arrival of the French Revolutionary forces in 1794 meant the end of the abbey, which was suppressed, plundered and reused as a military hospital.
Through various individual proprietors the former abbey grounds became the property in 1824 of the Onze-Lieve-Vrouwekerk (Church of Our Lady) in Sint-Truiden, which sold the whole complex in 1839 to the diocese of Liège.
In 1845 a new Neo-classical seminary church was built on the site of Saint Trudo's original, the fourth in this place.
In 1975 a catastrophic fire severely damaged the Baroque abbey buildings and destroyed the 1845 seminary church.