Under the rules of emperors Domitian (81-96 AD) and Hadrian (117-138 AD) the Romans pushed the border of their province Raetia farther to the North. They expanded the wall of Limes in order to protect against the Germanic peoples and equipped it with many watchtowers, and in the immediate vicinity of Hesselberg large Castella were built. Under the rule of emperor Caracalla (around 213 AD) the last and widest extension of the Limes took place. To the west of the mountain the wall crossed the rivers Wörnitz and Sulzach in a north-south direction. A few kilometres to the north of Wittelshofen it turned eastward. Due to this sharp bend the strategically important Hesselberg was included within the Roman Empire. There were Castella at Aufkirchen, Ruffenhofen, Dambach, and Unterschwaningen. Castellum Ruffenhofen was the largest in the Hesselberg area. No Roman buildings have been found by archaeologists on the mountain itself. The remains of the Limes now form stone ridges hidden in the woods. Nowadays most of the civil and military wall remains are hidden beneath the ground of local meadows and fields. On top of Castellum Ruffenhofen a Roman park is built. In the local museum of Weitlingen there are a few Roman exhibits.