Bury—On the Roman Empire in Fourth Century, A.D. 505 
of Italy in 368, 369, 370, 3871, 372, 374. We learn from Ammianus 
(xxvit. 7, 1) that Mamertinus was still praetorian prefect in 367, but 
in that year was accused of peculation, and succeeded by Vulcatius 
Rufinus, who died in the following year, and was succeeded by Probus 
(ib., 11, 1). Ammian mentions him again as praetorian prefect in 
378 and 874 (xxix. 6, 9, praefectus practorio agens tunc apud Sirmium ; 
xxx. 3, 1, praefecti relatio Probi docentis Ilyrici clades). 
We find Probus mentioned in some inscriptions : 
C. I. L., vol. v., 83844; Petronio Probo V.C. totius admirationis 
viro proconsuli Africae praef. praetorio Illyrici praef. praet. Galli- 
arum IT. praef. praet. Italiae atque Africae III., &c. (at Verona). 
Henzen, 6418; procons. Africae praefecto praetorio per Illyricum 
Ttaliam et Africam (4.D. 378). 
Marini, ined. Alb. p. 59; praefecto praetorio quater Italiae, 
Ilyrici, Africae, Galliarum. 
That no final separation was made between Italy and Illyricum 
until 395, when the empire was divided, is proved by the fact that 
we find Polemius praetorian prefect of Italy and Illyricum in 390, 
similarly Tatianus in 391-2; Apodemius in 392-3: see Cod. Theod. 
I have attempted to show that no definite division of the empire 
into four prefectures, such as has been always attributed to Constan- 
tine, was ever designedly made, and that such a division did not 
unalterably exist until after 395. The four divisions of the Wotztia 
Dignitatum were not finally stereotyped by Constantine, although 
Constantine contributed to fix them; they are natural seographical 
divisions, and their origin must be traced to Diocletian. ‘The institu- 
tion of four praetorian prefects was never determined by ordinance, it 
followed, so to speak, as an accidental consequence of other events. 
Weare entitled to say that the precedent of four prefectures originated 
with Constantine, but we are not entitled to attribute it to him as an 
artificial enactment——like the division e. g. into dioeceses. The locali- 
sation of the prefects and the increase of their number were con- 
sequences naturally entailed by the arrangement of Diocletian and the 
curious series of wars and political complications which followed his 
abdication. The increase in number and the localisation came to pass 
in the natural course of events, and Constantine made no enactment 
either to stereotype or to change these results. He simply took ad- 
vantage of the new state of things, and administered in the spirit of 
the time, whereby of course he indir ectly contributed to render familiar 
the already existent idea of three or four prefectures. His institution 
of four Caesars involved four praetorian prefects. But this precedent 
was so far from becoming a statute or definite enactment, that from the 
time of his death to the ipartition of the Empire, in 395, there were 
sometimes three prefectures and sometimes four. It is quite possible 
that, if events had not brought about the separation of the Western 
from the Eastern Empire, three prefectures might have finally become 
by usage a fixed institution. 
a 
