INTRODUCTION
PART I: APPROACHING THE PERIODThe division between east and westIn the year AD 395 the Emperor Theodosius I died, leaving two sons, both
of whom already held the rank of Augustus. Arcadius became emperor in the
east and Honorius in the west. From then on the Roman empire was effec-
tively divided for administrative purposes into two halves, which, as pres-
sure on the frontiers increased through the fifth century, began to respond in
significantly different ways. AD 395 was therefore a real turning point in the
eventual split between east and west.^1
Until then, and since the time of Diocletian (284–305), the late Roman
empire had been a unity, despite having at times a multiplicity of emperors, and
embracing all the provinces bordering on the Mediterranean and much more
besides (Map 0.1). While Constantine had made himself sole emperor by elimi-
nating his rivals, and thus destroyed the tetrarchic system from which he had
emerged himself, there were often multiple emperors in the fourth century, and
the idea that emperors had their own territorial spheres and bases was not new.
However, Theodosius himself (379–95) had not hesitated to move from Con-
stantinople to the west when it was necessary to deal with potential challenges,
and there had not been a formal division. In the west the empire stretched as
far as Britain and included the whole of Gaul and Spain, while in the north the
frontier extended from Germany and the Low Countries along the Danube to
the Black Sea. Dacia, across the Danube, annexed by Trajan in the early second
century, was given up at the end of the third after a series of Gothic invasions,
but otherwise the empire of Diocletian was impressively similar in extent to that
of its greatest days in the Antonine period. To the east, it stretched to eastern
Turkey and the borders of the Sasanian empire in Persia, while its southern pos-
sessions extended from Egypt westwards to Morocco and the Straits of Gibral-
tar; Roman North Africa (modern Algeria and Tunisia) was one of the most
prosperous parts of the empire during the fourth century.
In Diocletian’s day, though Rome was still the seat of the senate, it was no
longer the administrative capital of this large empire. Emperors moved from