In much of Europe the Roman Frontier followed the Rhine and the Danube rivers. To shorten communications and to control some areas rich in agricultural resources the Romans created a land frontier over 500 km long with some 900 watchtowers and 120 forts between the upper reaches of the Rhine and the Danube. Begun under the orders of the emperor Hadrian in the second century, by the middle of the 3rd century the frontier had been largely overrun by barbarian tribes.
The area was brought under direct control of the Romans around 85 AD when the oldest part of the Limes was created between the River Rhine and the high Taunus Mountains. This early Limes barrier seems to have been a cleared stretch of forest monitored by wooden towers. Under the emperor Hadrian (117-138 AD) a palisade fence was constructed in Upper Germany in a mathematically straight and unbroken line which even today often forms an important and defining element in the landscape. In what is now Bavaria, along the Raetian Limes, a palisade was erected later and was then replaced by a stone wall in the early 3rd century AD. For 52 kilometres the frontier followed the river Main.
Behind and along these linear barriers over 900 watchtowers and 120 forts and fortlets were constructed, towns developed and farms established. At its greatest extent the Limes line ran over 500 kilometres from the river Rhine north of Koblenz, through the Westerwald and Taunus forests, the Wetterau, along the River Main, through the forest of the Odenwald and the Swabian-Franconian Jura. It encloses the fertile lands of the Noerdlinger Ries and ended at the River Danube near Kelheim.
More a guarded border line than a military defence system, the Limes enabled traffic to be managed, movement of people controlled and goods traded and taxed. Increasing pressure caused by barbarian tribal movements from the east and internal conflicts within the Empire led to the collapse of this part of the frontier in the late third century AD.
The many fine objects displayed in high quality museums are testament to the former power and splendour of Rome and to the often brutal collapse of the frontier in the third century. Virtual reconstructions at various museums provide a vivid picture of daily life at the edge of the Empire, whereas out in the countryside the visible remains, reconstructed watchtowers, forts and buildings, information panels and smartphone applications bring the Roman past to life.
The varied landscapes through which the Limes line passes, and the fascinating Roman heritage offer great walking and cycling opportunities. Many of these areas retain their special rural character and offer the visitor high quality local produce to eat and drink. Much of the line of the Limes is followed by the Limestrasse road which links many fine traditional towns and villages and there are many signposted footpaths and cycleways.