Germania Inferior

The principal settlements of the province were Castra Vetera and Colonia Ulpia Traiana (both near Xanten), Coriovallum (Heerlen), Albaniana (Alphen aan den Rijn), Lugdunum Batavorum (Katwijk), Forum Hadriani (Voorburg), Ulpia Noviomagus Batavorum (Nijmegen), Traiectum (Utrecht), Atuatuca Tungrorum (Tongeren), Bona (Bonn), and Colonia Agrippinensis (Cologne), the capital of Germania Inferior.

The first confrontations between a Roman army and the peoples of Germania Inferior occurred during Julius Caesar's Gallic Wars.

[2] Although this region had been occupied since the reign of Augustus, it wasn't formally established as a Roman province until around AD 85, with its capital at Colonia Claudia Ara Agrippinensium (modern-day Cologne).

The Roman Navy's Classis Germanica (Germanic fleet), charged with patrolling the Rhine and the North Sea coast, were based at Castra Vetera and later at Colonia Claudia Ara Agrippinensis.

Its capital remained at Colonia Claudia Ara Agrippinensium, which also became the seat of a Christian bishopric, which was in charge of an ecclesiastical province that survived the fall of the Western Roman Empire.

Borders of the Germania Inferior, with main roads and cities/forts
Several different regions called Germania in the Roman era
The Roman empire in the time of Hadrian (ruled 117–138), showing, on the lower Rhine river, the imperial province of Germania Inferior (NW Germany/S. Netherlands, E. Belgium), and the three legions deployed there in 125. Note that the coast lines shown in the map are those of today, known to be different from those in Roman times in the North Sea area.