 In 264 BC, Roman Italy extended from the Arno and Rubicon rivers of the centre-north to the entire south.The northern area of Cisalpine Gaul was occupied by Rome in the 220s BC and became considered geographically and "de facto" part of Italy, but remained politically and "de jure" separated.It was legally merged into the administrative unit of Italy in 42 BC by the triumvir Octavian as a ratification of Caesar's unpublished acts ("Acta Caesaris").