Belgica, one of three Gallic provinces organized by Julius Caesar; it became one of the four provinces ofGaul under the Roman Empire. As established byAugustus (27bc), Belgica stretched from theSeine River eastward to the Rhine and included theLow Countries in the north and the Helvetian territory (western Switzerland) in the south. Its capital was Durocortorum Remorum (nowReims, France). Under the Roman emperorDomitian (ad 81–96), large portions of Belgica along the lower and upper Rhine were made into the separate provinces of GermaniaInferior and Germania Superior, respectively. UnderDiocletian (c.ad 300), the remainder was divided into Belgica Prima (capital,Augusta Treverorum [now Trier, Ger.]) and Belgica Secunda (capital, Durocortorum Remorum). In the 5th century, Belgica was absorbed into the kingdoms of the Salian and Ripuarian Franks.