In common usage the reign of Augustus is regarded as the foundation of the Roman Empire. […] No province of the Empire was immune from his control. […] Instead, he would set out for the wars again, to Macedonia and to the eastern frontier of the Empire. […] Rice Holmes, The Architect of the Roman Empire 1 (1928), 192 ff. […] Rice Holmes, The Architect of the Roman Empire 1 (1928), 191, on Ad Att. 15, 3, 2 (May 22nd).