The BeNeLux is older than Schengen (september 1944, founded by the governments of Belgium/Netherlands/Luxembourg while in exile from their occupied countries!).

The BeNeLux is older than Schengen (september 1944, founded by the governments of Belgium/Netherlands/Luxembourg while in exile from their occupied countries!). It eliminated border controls between Belgium and the Netherlands. Before that, I don't know and can't find them at the moment. Before the 20th century border controls didn't really exist yet. In WW1 the situation was special because Belgium was under German occupation but the Netherlands were neutral, the Belgian enclaves were bits of free Belgium heavily used by the resistance. To prove their neutrality the Netherlands were forced to put a fence around it with strict controls.