Roman colonization of the Main valley and Odenwald

By the reign of the Emperor Claudius (AD 41-54) the Romans were firmly established along the Rhine and the Danube and using them as convenient ‘natural’ frontiers. Nevertheless they had sufficient sense of geography to realize that an awkward wedge-shaped tract of land lay between the Rhine where it flowed north through Germania superior and the upper reaches of the Danube that flowed east and bounded Raetia13 (Fig. 4). Much of this land was covered by the Odenwald. Although ominously hilly and densely forested it had apparent potential for colonization and food production, so, in characteristic fashion, they decided to straighten out the line of frontier. In effect, they would replace a ‘wet limes’ with a land-based limes.

In simplified terms, the subsequent Roman incursions beyond the Rhine took place in three main stages (Fig. 5). Firstly, during the reign of Emperor Vespasian (AD 69-79), the southernmost re-entrant angle of land that we know today as the Black Forest (Schwarzwald) was invaded and settled. Further north, the grip on the east bank of the Rhine was strengthened and advances made into the fertile valley of the river Main (Moenus), pushing back the troublesome and aggressive Chatti tribe that had once supported Arminius.

Fig. 5 – Final course of the Limes relative to Germania Superior and Raetia.

In AD 83-5, during the reign of Domitian, a second phase becomes apparent. Six legions from Mogontiacum (Mainz) struck further up the river Main and its tributaries, again pushing back the Chatti. This Chattan war was the last great military campaign into Free Germany (Germania magna). A chain of isolated watchtowers, typically 200-1000 metres apart, was established along the crest line of the Taunus mountains. This marks the beginnings of the construction of the Limes which ran from present-day Rheinbrohl on the Rhine, about 10 km from Remagen, to form a great salient in the Main valley. Around AD 100, the line of fortification then struck south for 50 km alongside the Main and, as a spur, into the heart of the Odenwald forests, meeting the river Neckar (Nicer) near Wimpfen. As intended, this Odenwald – Limes dramatically shortened the frontier and lateral lines of communication, thus helping to shield the vulnerable eastern flank of Germania superior (Upper Germany). Emperor Hadrian (AD 117-38), that indefatigable traveller, came to the Odenwald frontier in AD 121-2 and ordered the erection of a stout wattle hedge or palisade of stakes along its entire length. This introduction of a continuous barrier set a crucial precedent. As it left the Odenwald and the upper reaches of the river Neckar, the Limes swung sharply eastward to form the northern border of Raetia, with a belt of forts stretching overland toward the key legionary fortress of Castra Regina (Regensburg) on the Danube.

The third and final phase of eastward movement took place in the Odenwald during the reign of Antoninus Pius (AD 138-61). Around AD 155, the Upper Germanic – Limes was established about 20 km to the east of the Odenwald – Limes of Domitian (Fig. 5). Here, at the eastern edge of the Odenwald, the terrain is undulating and more open (Fig. 6). It is here that we marvel at the skill of the Roman surveyors and their close attention to line of sight along the Limes. The straight run of Antonine fortification which runs for 80 km from Walldürn to Weltzheim is a case in point14. A modern surveying exercise over a 30 km-long section showed that its deviation from the straight did not exceed one metre. The Odenwald territory was largely colonized and farmed by Gauls and came to be known as the Agri Decumates, customarily translated as the ‘Land of the Ten Cantons’.

Fig. 6 – Odenwald landscape west of Rinschheim village on the Upper Germanic Limes.

  1. Raetia adjoined Germania superior and included the upper Danube, the Alps and much of present-day Bavaria. []
  2. Obergermanish-Raetischer Limes in Baden-Württemberg maps, scale 1:50000, UNESCO-World Culture Heritage, ISBN 3-89021-745-1 (Landesvermessungsamt Baden-Württemberg, Stuttgart): this coloured set of maps is beautifully detailed. []