One of the town’s oldest abbeys, it was built by the Merovingian queen Brunehaut in the late 6th century, with a large church dating back to 1175, and an abbot’s residence dating back to 1771.Hard-hit through the ages (it was burnt down three times, in the 9th century, during the 100 Years’ War and in 2008), Henri IV used it during the siege of Laon, and it was transformed into an arsenal in 1880… Among its features, it shelters on its site a pond which delighted the naturalist Buffon, as its level never dropped… The site was the subject of an excavation campaign in 2021, and is now the property of the City of Laon, which has equipped its exterior walls with panels recounting the site’s history… (building only visible from the outside)