This was the greatest victory which Rome had won in the East since the campaigns of Trajan and Vespasian. It was followed by fifty years of profound peace; and the ancient feud between Rome and Parthia was not renewed until the closing days of the reign of Constantine. Lactantius, of whose credibility as a historian we shall speak later on, sneers at the victory of Galerius, which he says was “easily won”[4] over an enemy encumbered by baggage, and he represents him as being so elated with his success that when Diocletian addressed him in a letter of congratulation by the name of Cæsar, he exclaimed,[5] with glowing eyes and a voice of thunder, “How long shall I be merely Cæsar?” But there is no word of corroboration from any other source. On the contrary, we can see that Diocletian, whose forte was diplomacy rather than generalship, was on the best of terms with his son-in-law, Galerius, who regarded him not with contempt, but with the most profound respect. Diocletian and Galerius, for their lifetime at any rate, had settled the Eastern question on a footing entirely satisfactory and honourable to Rome. A long line of fortresses was established on the new frontier, within which there was perfect security for trade and commerce, and the result was a rapid recovery from the havoc caused by the Gothic and Parthian irruptions. ----- Footnote 4: _De Mort. Persec._, c. 9: _Non difficiliter oppressit._ Footnote 5: _Truci vultu ac voce terribili, Quousque tandem Cæsar?_ ----- Though Diocletian had divided the supreme power, he was still the moving and controlling spirit, by whose nod all things were governed.[6] He had chosen for his own special domain Asia, Syria, and Egypt, fixing his capital at Nicomedia, which he had filled with stately palaces, temples, and public buildings, for he indulged the dream of making his city the rival of Rome. Galerius ruled the Danubian provinces with Greece and Illyricum from his capital at Sirmium. Maximian, the Augustus of the West, ruled over Italy, Africa, and Spain from Milan; Constantius watched over Gaul and Britain, with headquarters at Treves and at York. But everywhere the writ of Diocletian ran. He took the majestic name of Jovius, while Maximian styled himself Herculius; and it stands as a marvellous tribute to his commanding influence that we hear of no friction between the four masters of the world. ----- Footnote 6: _Cujus nutu omnia gubernabantur._ -----