Castellum Menapiorum: main settlement of the Belgian Menapii, modern Cassel in northern France.
Situated on a hilltop, Castellum Menapiorum ("castle of the Menapii") was the main settlement of the Menapii, a Belgian tribe that was subjected by Julius Caesar. Roads connected the town with the ports of the Channel, the cities of the Meuse valley, and the Mediterranean South. Castellum Menapiorum prospered in the early Roman period but was also attacked by Germanic raiders.
New fortifications did not offer sufficient safety and the official function of the town, capital of the Menapii, was transferred to Tournai in the interior, which king Childeric made he most important city in the region in the late fifth century. Castellum Menapiorum remained occupied as fortress.