INTRODUCTION TO SOCIOLOGY 413
social equilibrium is by definition a living and unstable equi- librium.
The same continuous changes occurred in the Mediterranean world. Since 476 there had been no emperor at Rome; the Roman Empire of the East persisted. In 533 it reconquered Africa, Sardinia and Corsica, and the Balearics from the Vandals ; in 535. Sicily and Dalmatia from the Ostrogoths; from 536 to 553 it regained the whole of the Italian peninsula, with the excep- tion of the northern part of the old diocese of Italy, that is to say, Raetia, Noricum, and Pannonia. In 554 it had retaken all of the southeast of Spain from the Visigoths, and it extended beyond the Guadalquivir. It was a real offensive return of the old empire, but its center was at Byzantium, and the force of this return scarcely made itself felt in the West. At the accession of Justinian there were sixty-four provinces, grouped in six dio- ceses, which were again divided between two pretorian pre- fectures, that of Illyria and that of the East, the latter the more extensive. These divisions were neither ethnic nor geographical. After the reconquest of Africa, seven new provinces were estab- lished with one prefecture; after that of Italy, twelve provinces and one prefecture. Under these conditions, Justinian restored to Rome her old privileges; but peoples and regions were con- fused without regard to their ethnical affinities or to geographical regions. The true delimitations were of another sort; the civil and military powers were everywhere clearly separated; quite in contrast with the old imperial policy, the provinces might from this time become more extended, without this extension, thanks to the separation of powers, presenting any dangers.
However, in the administrative districts where the domina- tion lacked complete stability, and especially in those bordering upon the frontiers, the two powers, civil and military, were reunited. This system was even extended at times to Italy and to Africa in case of necessity. It is always, in fact, upon the fron- tiers, where instability relative to internal forces is the greatest, that military force tends to appear. From here this military force tends also to impress its authoritative character upon the whole internal social structure, and even at times, as we see in the case
