Northern Italy was called by different terms in different periods of history. During ancient times the terms Gallia Cisalpina, Gallia Citerior or Gallia Togata were used to define that part of Italy inhabited by Celts (Gauls) between the 4th and 3rd century BC. Conquered by the Roman Republic in the 220s BC, it was a Roman province from c. 81 BC until 42 BC, when it was merged into Roman Italy. Until that time, it was considered part of Gaul, precisely that part of Gaul on the "hither side of the Alps" (from the perspective of the Romans), as opposed to Transalpine Gaul ("on the far side of the Alps").