The Provinces of the Roman Empire (Illustrated Edition). Theodor Mommsen
settlements were not tolerated. Thereupon individual, mostly Gallic, immigrants, who had not much to lose, settled down, as on an unenclosed moor, in these fertile but little protected regions, which went at that time by the name of agri decumates.77 This private occupation, which was, it may be conjectured, merely tolerated by the government, was followed by the formal taking possession of it probably under Vespasian. As already, about the year 74, a highway was carried from Strassburg on the right bank of the Rhine as far as Offenburg,78 there must have been instituted about this time in this region a more earnest protection of the frontier than the mere prohibition of Germanic settlement furnished. What the father had begun the sons carried out. Perhaps even through the construction—whether by Vespasian, by Titus, or Domitian—of the “Flavian altars”79 at the source of the Neckar, near the modern Rottweil—a settlement of which indeed we know nothing but the name—there was procured for the new upper Germany on the right of the Rhine a centre similar to what the Ubian altar was formerly intended to become for Great Germany, and soon afterwards the altar of Sarmizegetusa became for the newly–conquered Dacia. The first institution of the frontier–defence, to be described further on, by which the Neckar valley was brought within the Roman line, is thus the work of the Flavii, chiefly, doubtless, of Domitian,80 who thereby carried further the construction at the Taunus. The military road on the right of the Rhine from Mogontiacum by way of Heidelberg and Baden in the direction of Offenburg—the necessary consequence of this annexation of the Neckar region—was, as we now know,81 constructed by Trajan in the year 100, and was a part of the more direct communication established by that emperor between Gaul and the line of the Danube. There was employment for the soldiers at these works, but hardly for their arms; there were no Germanic tribes dwelling in the region of the Neckar, and still less can the narrow strip on the left bank of the Danube, which was thereby brought within the frontier line, have cost serious struggles. The nearest Germanic people of note there, the Hermunduri, had more friendly dispositions towards the Romans than any other tribe had, and carried on lively commercial intercourse with them in the town of the Vindelici, Augusta; of the fact that this advance met with no resistance from them, we shall find traces further on. Under the following reigns of Hadrian, Pius, and Marcus, further progress was made with these military arrangements.
The upper Germanic Limes.
We cannot historically follow out the mode in which the frontier–fence between the Rhine and the Danube—still in great part subsisting as regards its foundations at the present day—came into existence, but we are able to recognise not merely the course which it took but also the purpose which it served. The work was as to its nature and purpose different in upper Germany from what it was in Raetia. The upper German frontier–fence, with a length in all of about 250 Roman miles (228 English miles82) begins immediately at the northern boundary of the province, embraces, as has been already said, the Taunus and the plain of the Main as far as the district of Friedberg, and turns thence southward to the Main, which it meets at Grosskrotzenburg above Hanau. Following the Main thence as far as Wörth, it here takes the direction of the Neckar, which it reaches somewhat below Wimpfen and does not again leave. Afterwards in front of the southern half of this frontier–line a second was laid out, which follows the Main by way of Wörth as far as Miltenberg, and thence is led for the most part in a straight direction to Lorch between Stuttgart and Aalen. Here to the upper German frontier–fence is joined on the Raetian, only 120 miles (108 English) long; it leaves the Danube at Kelheim above Ratisbon and runs thence, twice crossing the Altmuhl, in a curve westward likewise as far as Lorch.
The upper Germanic Limes consists of a series of forts which are distant from each other, at the most, half a day’s march (about nine English miles). Where the lines of connection between the forts are not closed by the Main or the Neckar, as stated above, there was introduced an artificial barrier, at first perhaps merely by a palisade,83 afterwards by a continuous earthen rampart of moderate height, with a fosse outside and watch–towers built in at short intervals on the inner side.84 The forts are not introduced into the rampart, but constructed immediately behind it at a distance seldom exceeding one–third of an English mile.
The Raetian Limes.
The Raetian frontier–fence was a mere barrier, produced by piling up quarry–stones; there were no fosses or watch–towers, and the forts, constructed behind the Limes without regular succession and at unequal intervals (none nearer than two and a half to three miles), stand in no immediate connection with the barrier–line. As to the order in time of the constructions there is no definite testimony; it is proved that the upper Germanic line of the Neckar was in existence under Pius,85 that placed in front of it from Miltenberg to Lorch under Marcus.86 The idea of a frontier–bar was common to the two structures, otherwise so different; the preference in the one case for the piling up of earth—whence the fosse for the most part resulted of itself—in the other case, for layers of stone, probably depended only on the diversity of the soil and of the materials for building. It was common to them, further, that neither the one nor the other was constructed for the defence, as a whole, of the frontier. Not merely was the hindrance, which the piling up of earth or stone presented to the assailant, slight in itself; but along the line we meet everywhere with commanding positions, morasses lying in the rear, a want of outlook towards the country in front, and similar clear indications of the fact, that in the tracing of it warlike purposes generally were not contemplated. The forts are of course arranged for defence, each by itself, but they are not connected by paved cross–roads; and so the individual garrison relied for support not on those of the neighbouring forts, but on the rear–base, to which the road led, whereby each was kept garrisoned. Moreover, these garrisons were not dovetailed into a military system of frontier defence; they were rather fortified positions for a case of need than strategically chosen for the occupation of the territory, as indeed the very extent of the line itself, compared with the number of troops at disposal, excludes the possibility of its defence as a whole.87
Object of these structures.
Thus these extensive military structures had not, like the Britannic wall, the object of checking the invasion of the enemy. The intention rather was, that, like the bridges over the river–frontier, so the roads on the land–frontier should be commanded by the forts, but in other respects, like the river as the water–boundary, so the wall on the landward should hinder the uncontrolled crossing of the frontier. Other uses might be combined with this; the preference, often apparent, for the rectilineal direction points to its application for signals, and occasionally the structure may have been used directly for purposes of war. But the proper and immediate object of the structure was to prevent the crossing of the frontier. The fact, withal, that watch–posts and forts were erected, not on the Raetian but on the upper Germanic frontier, is explained by their different relations to the neighbours, in the former case to the Hermunduri, in the latter to the Chatti. The Romans in upper Germany did not confront their neighbours as they confronted the Highlanders of Britain, in whose presence the province was always in a state of siege; but the repulse of predatory invaders as well as the levying of the frontier–dues demanded at any rate ready and near military help. The upper German army, and in keeping with it the garrisons on the Limes, might be gradually reduced, but the Roman pilum could never be dispensed with in the land of the Neckar. It might, however, be dispensed with in presence of the Hermunduri, who, in Trajan’s time, alone of all the Germans, were at liberty to cross the frontier of the empire without special control and to trade freely in the Roman territory, especially in Augsburg, and with whom, so far as we know, border–collisions never took place. There was thus at this period no occasion for a similar structure on the Raetian frontier; the forts north of the Danube, which can be shown to have subsisted already in Trajan’s time,88 sufficed here for the protection of the frontier and the control of frontier–intercourse. This accords with the observation that the Raetian Limes, as it stands before our eyes, corresponds only with the more recent upper Germanic barrier–line perhaps laid out for the first time under Marcus. Then occasion for it was not wanting. The wars of the Chatti, as we shall see (p. 161), seized at this time also on Raetia; the strengthening too of the garrison of the province might reasonably stand in connection with the erection of this Limes, which, however little it was arranged for military ends, was at any rate doubtless constructed with a view to its being a frontier–bar, though of less strong character.89
Their effect.
In