Nice example of this early miniature map of Gallia Belgica, published in Amsterdam by Bertius.
Gallia Belgica ("Belgic Gaul") was a province of the Roman Empire located in the north-eastern part of Roman Gaul, in what is today primarily northern France, Belgium, and Luxembourg, along with parts of the Netherlands and Germany.
In 50 BC, after the conquest by Julius Caesar during his Gallic Wars, it became one of the three newly conquered provinces of Gaul (known as the Tres Galliae (the 3 Gauls), the other two being Gallia Aquitania and Gallia Lugdunensis). An official Roman province was later created by emperor Augustus in 22 BC. The province was named for the Belgae, as the largest tribal confederation in the area, but also included the territories of the Treveri, Mediomatrici, Leuci, Sequani, Helvetii and others. The southern border of Belgica, formed by the Marne and Seine rivers, was reported by Caesar as the original cultural boundary between the Belgae and the Celtic Gauls, whom he distinguished from one another.
The province was re-organized several times, first increased and later decreased in size. Diocletian brought the northeastern Civitas Tungrorum into Germania Inferior, joining the Rhineland colonies, and the remaining part of Gallia Belgica was divided into Belgica Prima in the eastern area of the Treveri, Mediomatrici and Leuci, around Luxembourg and the Ardennes, and Belgica Secunda between the English channel and the upper River Meuse.