The Dominate and the Fall of the West (ad 284-476)

(1) Diocletian and the Dominate

Such events are not conducive to long-term peace and prosperity, and it is almost a miracle that the Empire survived the Crisis of the Third Century.

Diocletian reorganised imperial government at all levels. He restructured pro­vincial administration and expanded the civil service. He was not successful in all of his schemes — a notable failure was his edict on prices in AD 301, which was unsuccessful in controlling prices and wages — but, particularly in contrast with the upheavals of the previous fifty years, he was astoundingly successful. A mark of his success was that he was able to abdicate at a time of his own choosing (in AD 305), living out his days peacefully growing cabbages and trying to avoid getting drawn back into politics.

Diocletian’s most enduring reform was his division of the Empire into eastern and western parts. Realising that the Empire was too big for a single person to govern, he appointed a co-emperor (Maximian).

The Tetrarchy system did not long survive Diocletian’s abdication in points of detail. However, subject to some interruptions, when a single man managed to establish sole control over the whole Empire, this division into east and west became an established feature.

(2) Constantine and the Conversion to Christianity

One of these interruptions in fact came very soon after Diocletian’s abdication, with the emperor Constantine. He was proclaimed western emperor in AD 306, and established himself as such by 312 by defeating his rivals. Following civil war, he established himself as sole emperor in 324.

Constantine is one of the major figures of the Dominate, and had clear ambition. He established a new capital at the ancient city of Byzantium, which he called Constantinople after himself. This is modern Istanbul, and is another sign of the eastward shift in the Empire's centre of gravity.

The most important development of Constantine's reign, however, was the adoption of Christianity. We have already seen the emergence of Christianity in the Principate, as a group prominent enough to attract periodic persecution but still very much a minority Indeed, there was major state-sanctioned persecution as late as Diocletian's reign. This was all to change dramatically under Constantine.

The consequences of this were profound. From being a persecuted minority, although by now a substantial one, Christians were thrust into political promi­nence. This naturally made Christianity much more attractive to the politically ambitious. It is notable that only one emperor after Constantine was a pagan, Julian the Apostate (reigned AD 361—3). The political influence of Christianity in the fourth century was spectacularly demonstrated when Bishop Ambrose of Milan excommunicated the eastern emperor, Theodosius I,^[73] for ordering a massacre of thousands of civilians in 390, only readmitting him after months of penance. The very idea of a repentant Roman emperor, on his knees before a Christian bishop, would have seemed absurd — indeed unimaginable — to earlier generations.

(3) The Fall of the Western Empire

Ultimately, the Empire was not able to withstand the challenges that faced it. Power sharing between eastern and western emperors rarely worked well. Theodosius I was the last man to be emperor of both halves of the Empire.^[74] There was a tendency for the two halves to be run, defacto, as separate empires, and after Theodosius I each was regarded as supreme in his own half.

By this time, though, the Western Empire had entered its final decline. Much ink has been spilled over the reasons for the fall of the Western Empire, more than can be satisfactorily explored here.^[75] Whatever the underlying reasons, though, the brute fact is that in the fifth century AD the Western Empire could no longer rely on its ability to defend its borders or exert authority over its territory. Germanic tribes outside the Empire's borders sought to move into the Empire, hoping to share in its benefits. The Empire was unable to exclude them, or to control them once they entered. Piece by piece, the Western Empire crumbled. In AD 410, Rome itself was sacked by the Visigoths. In the same year, the inhabit­ants of the Roman provinces of Britannia were told that they would need to look to their own defence for the time being. The withdrawn Roman troops never returned, and from the middle of the century onwards what is now England was largely overrun by invading Germanic tribes, the Anglo-Saxons (who give England its name). Throughout the century, Roman control retreated. The final step came in AD 476, when the final western emperor, Romulus Augustulus, was deposed by the barbarian leader Odoacer and not replaced.

H.