Lecture 2

This division of the Empire into two parts, one mainly Latin, the other mainly Greek, lasted for 150 years; it was for the greater part of that time ruled by two emperors, occasionally it was under one. But throughout all this period there were the two seats of government, one at the old Rome on the Tiber, the other at the new Rome on the Bosphorus; and the two governments, their systems, their organisations, their officials were exactly the same; one was virtually the replica of the other. That was a very remarkable, indeed a unique, experiment in government; an empire ruled not from one centre, but from two foci, through two parallel organisations. The two parts are often loosely spoken of as if they were two distinct Empires---the eastern and the western. That is a mistake against which we must be on our guard. The unity of the two parts was always most carefully maintained. The Roman Empire was always considered one and indivisible. It never entered anyone's head to think of two. The unity was maintained and expressed in various ways, particularly in legislation. When a law was passed at Constantinople, it was issued not merely in the name of the emperor who was ruling there but in the joint names of him and the emperor ruling in the west; and conversely. The old practice of appointing two consuls at the beginning of every year was preserved, and one of them was nominated at Rome and the other at Constantinople.

The renovated Empire received a new organisation, the result of reforms partly due to Diocletian and partly to Constantine. The general result was that for the purposes of civil administration the whole Empire fell into four great sections, two in the west and two in the east, known as prefectures, because each section was governed by a great minister entitled a praetorian prefect, who was responsible solely to the Emperor. The two western prefectures were the Guals and Italy, but each of these included many lands which we do not now associate with those names. The Prefecture of the Gauls included, as well as Gaul, Britain and Spain and the north-west corner of Africa---Morocco. The Prefecture of Italy included, as well as Italy, Switzerland and the provinces between the Alps and the Danube, and also the coast lands of North Africa. The two eastern prefectures were the Prefecture of Illyricum, which covered the Balkan peninsula, with the exception of Thrace, and was the smallest of the four; and the Prefecture of the Orient, which comprised Thrace and Egypt, and all the Asiatic territory that belonged to the Empire.

Each of these prefectures was divided into large districts called dioceses, each of the size of a fair-sized modern state. Thus in the prefecture of the Gauls there were four dioceses: Britain, two dioceses in Gaul, and Spain. And in each diocese was under a vicar, who was subject to the praetorian prefect. And in each diocese there were a number of provinces each under a provincial governor. Thus the whole system of civil government was, roughly speaking, a hierarchy, like a ladder, with the Emperor at the top, the provincial governor at the foot, and the praetorian prefects and the vicars as the intermediate steps---roughly speaking, for there were a number of exceptions and complications which we need not trouble about. For our present purpose what I have said is enough respecting the civil organisation, and its general hierarchial character. Only observe that there are two such systems, two of these hierarchies, one centring at Rome, the other at Constantinople, like two clocks similarly constructed but functioning independently. And it is important to remember that neither of these great civil administrations had any military functions. The separation of civil and military authority was one of the capital features which differentiated the new monarchy of the fourth and following centuries from the earlier empire of Augustus.

It is the military organisation of the Empire which it is of great importance for us to understand, and its German invaders. The principal feature in which the military establishment of the fourth and fifth centuries differed from that of the early Empire was the existence of a mobile army. While all the frontiers were defended by troops permanently stationed in the frontier provinces, distinguished as limitanei, there was also a field army which the Emperor could move to any part of his domain which happened to be threatened whenever war broke out; and these troops, which accompanied the Emperor in his movements and so formed an imperial retinue, or comitatus, were distinguished as comitatenses. Thus the military forces consisted of two main classes, the comitatenses, who were the most important when there was serious warfare, and the limitanei.

A second outstanding feature in the military organisation of the later Empire is the smaller size of the legionary unit. The strength of the old Roman legion, as it had hitherto been, was about 6000 men; and it was associated with a number of cohorts of infantry and squadrons of cavalry, all under the command of the legatus or commander of the legion, so that the legatus had about 10,000 men under him. All this is changed. The old legion of 6000 is broken up into detachments of 1000; new legions that are formed are only 1000 strong; the cohorts and the cavalry squadrons are under separate commanders.

Most important is the separation of the cavalry from the infantry, and its conversion into an independent arm instead of a subordinate one. All these armies were under the supreme command of Masters of Soldiers, Magistri Militum. It is usual to translate this term literally; they correspond in rank to what we call Field-Marshals, but they had definite commands, and here the systems in the west and in the east developed rather differently. As this office will constantly be mentioned in these lectures it is necessary to explain briefly its position both in the east and in the west---as it was just before the end of the fourth century.

In the east there were five Masters of Soldiers. Two of these resided at Constantinople and commanded the troops of the field armies stationed in the immediate neighbourhood of the capital. They were distinguished as Magistri in praesenti, i.e. in immediate attendance on the Emperor. The other three were stationed in the large districts of the east, Thrace, and Illyricum respectively, and commanded the troops stationed in them.

In the west it was different. Here we do not find five co-ordinate commanders, but two, magistri militum in praesenti, whose headquarters were in Italy; one was commander of the infantry, magister peditum, the other of the cavalry, magister equitum. But though nominally co-ordinate, the first, the Master of Foot, was much the more important. He had supreme authority not only over the mobile infantry of the west, but also over the commanders of infantry of the west, but also over the commanders of the limitanei. Towards the end of the fourth century he acquired superior authority over his colleague the Master of Horse, and thus supreme command of all the military forces of the west, and received the title magister utriusque militiae, Master of Both Services. i.e. both infantry and cavalry.

This difference in organisation had grave political results. In the west the concentration of military power in the hands of one man made the Master of Both Services the most important and influential minister, the man who really directed the policy of the state, and from the close of the fourth century up to the time when the western half of the Empire had completely passed into the power of the Germans, not only the defence of the Empire but the general management of its affairs was in the hands of a succession of soldiers, Masters of Both Services, who were sometimes a danger to the throne. In the east, on the other hand, there are a few cases, but not many, in which a Master of Soldiers attained to undue power.