The Main Limes (), also called the Nasser Limes, was built around 90 AD and, as part of the Upper Germanic-Rhaetian Limes, formed the frontier of the Roman Empire in the area between the present day villages of GroÃÂkrotzenburg and Bürgstadt. In this section the limes adjoined the River Main (Moenus), which forms a natural boundary for about 50 kilometres here, so "Main" refers to the river.
In order to secure the riverbank, it was sufficient to erect free-standing towers backed up by the forts of the units stationed nearby; there was never a continuous barrier of palisades and ditches here. However, of the many watchtowers that probably stood along the Main, to date only one south of Obernburg am Main has been identified. On the other bank of the Main was the largely uninhabited Spessart, a wooded hill range which, like the Odenwald which borders it to the south-west, was particularly interesting for the Romans, especially because of its timber. In inscriptions, there are reports of the logging vexillationes of the 22nd Legion, which were stationed in Obernburg, Stockstadt and Trennfurt.
In the majority of forts, settlement activity continued after the fall of the limes, which is why, as in Obernburg Niedernberg, Seligenstadt and GroÃÂkrotzenburg, they are now located below the medieval village centres. In Grosskrotzenburg, Hainstadt, Stockstadt and Obernburg, Alamannic artefacts were also discovered.
North of the Main the limes initially runs through the marshy terrain of the Schifflache and Bulau before linking up with the Wetterau Limes. At the crossing of the Main at GroÃÂkrotzenburg a Roman bridge has been identified from post sockets (Pfahlschuhe). In the south it extended in its early period to Obernburg or Wörth. The exact start point of the Odenwald Limes (Obernburg or Wörth) has still not been clearly identified. When the Odenwald Limes was abandoned in the 2nd century AD by Antoninus Pius and the establishment of the newer limes in the Bauland, the Main Limes was also extended, because the forts in Trennfurt and Miltenberg were added (newer Main Limes).
Because little remains of the forts, Roman artefacts are displayed especially in local museums such as Obernburg Romand Museum, Miltenberg Municipal Museum, Aschaffenburg Diocesan Museum and GroÃÂkrotzenburg Museum. Several fort sites such as Obernburg and Stockstadt have a rich collection of stone monuments.