An advanced bastion of France until 1678 when Valenciennes became French, the fortifications of Quesnoy were modified and reinforced by the very young Vauban who made in some way his "classes". The existing five bastions were amended or supplemented to create a body eight strong. The northern areas (Royal bastion) and south (Gard stronghold) are most representative of the action of Vauban. However, in the old regime of France where clientele took precedence over skills or even economy, the work was not awarded to local contractors.