490 Proceedings of the Royal Irish Academy. 
LX X.—Tue PrartortsN PREFECTS AND THE Divisions oF THE RoMAN 
Empire IN THE FourtH Century, a.p. By Joun B. Bury, M.A., 
Hea Co): 
[Read, December 13, 1886.] 
Ir is recorded by all modern historians that Constantine the Great 
divided the Roman Empire into four prefectures—Gaul, Italy, Ily- 
ricum, and the East—and thereby instituted four praetorian prefects 
instead of two. As to the division of the empire into dioceses, it is 
now generally admitted that we must ascribe it mainly to Diocletian ; 
the details may have been afterwards modified by Constantine. But 
historians feel no more doubt that Constantine definitely instituted the 
four prefectures than they feel that such a person as Constantine 
existed. 
When we ask what testimony exists to justify this certainty, we 
find that the only authority for the statement is the assertion of 
Zosimos, Bk. i. ¢. 82: 
ovvetapage dé Kal Tas waar Kabectapévas apxds . . . Kwvotav- 
Tivos 6¢ Ta KAAS KabeoTOTa KWOV pilav otcav és Téeroapas Siethev GpyXas. 
He goes on to enumerate the territories embraced in these four govern- 
ments, and then says: tavry dueAdpevos THY TOV brdpxuv | praefectorum 
praetorio| apxiv Kat dAdo tpdrwos eAaTTGcae Tavtny éeorovdoacer. 
Thus Zosimos makes the multiplication! of the praetorian prefects 
and consequent diminution of their power a subject of accusation 
against the Christian emperor. His statement as to the matter of 
fact is explicit; there can be no doubt about it. Historians are 
quite justified in accepting it as true—although Zosimos’ authority 
is by no means unimpeachable —provided they find no conflicting 
fact, resting on authority, which may be looked on either as cer- 
tain, or as less impeachable than Zosimos. If we do find a con- 
flicting statement better attested, that of Zosimos must fall. 
One thing, of course, is quite certain, namely, that the empire had 
been definitely divided into four prefectures before the end of the 
fourth century. The evidence of the Wotitia Dignitatum, drawn up 
at the beginning of the fifth century, makes this as certain as any 
fact of history can be. The question is: Was it definitely enacted by 
Constantine, as Zosimos alleges, that four praetorian prefects should 
1 The number had never been definitely limited to two. Since the time of 
Commodus it was customary to appoint oceasionally a third prefect: see Lampridius, 
V. Comm., Praefectus etiam Ebutianus inter hos est interemptus; im eujus locum 
ipse Cleander cum aliis duobus quos ipse delegerat praefectus est factus. Tuncque pri- 
num tres praef. praet. fuere ; and Spartianus, VY. Did. Jul., Ipse autem tertium 
Secit pracfectum Veturium Macrinum. 
