From 1624 to 1636, a large bastioned citadel was constructed on the site of the Abbey of Saint Vanne. In 1670, Sébastien Le Prestre de Vauban visited Verdun and drew up an ambitious scheme to fortify the whole city. Although much of his plan was built in the following decades, some of the elements were not completed until after the Napoleonic Wars. Despite the extensive fortifications, in the Battle of Verdun in 1792 the fortress was captured by the Prussians. This was during the War of the First Coalition. However it was abandoned by them after the Battle of Valmy. During the Napoleonic War, the citadel was used to hold British prisoners of war.