Barrier town
The barrier towns were present-day Belgian towns, heavily fortified by the Dutch, on the Austrian Netherlands's border with France, and as such were particularly important in the wars between the Dutch Republic and Ancien Régime France.
In the 1713 Treaty of Utrecht the allies conferred the conquered city of Tournai on the Netherlands for use as a barrier town..
The barrier towns were Veurne, Ypres, Menen, Tournai, Mons, Charleroi, Namur and the citadel of Ghent.
In the War of the Austrian Succession, France conquered these towns, but at the end of the war was forced to return them to the Netherlands by the 1748 Congress of Aix-la-Chapelle and the resulting Treaty.
Menen was a barrier town for the Kingdom of the Netherlands against France from 1815 to 1830.