For a stretch of about fifty kilometres the Romans let the River Main do the work of a wall. Between Miltenberg and Grosskrotzenburg, the frontier of the Upper Germanic Limes followed the river instead of running as a palisade across country, and a chain of forts sat along its west bank. Trennfurt, a village now part of Klingenberg am Main, was one of them: a fort with its civilian settlement, the vicus, where traders, craftsmen and soldiers' families lived. It is part of the UNESCO Frontiers of the Roman Empire, and as with many Limes sites, most of what survives lies under fields and gardens rather than standing proud.
What stands proud instead is the town. Klingenberg climbs steeply from the river, with half-timbered houses, narrow lanes and terraced vineyards on red sandstone slopes, crowned by the ruins of the Clingenburg castle. The local red wines, especially Spätburgunder, have a fine reputation, and the steep terraces were hard work to build and still are to tend.
Riding here means a mix of river valley and forest hills. The roads along the Main are easy and scenic, following the curves of the river past small towns like Wörth and Erlenbach, with good surfaces but plenty of traffic and towns with low limits. Cross the river or head west and you climb into the Odenwald, or east into the Spessart, both forested ranges with plenty of twisting roads that are popular with motorcyclists on summer weekends. Be wary of noise-related restrictions on some local routes and the attention police pay to popular biker roads.
Klingenberg has a few thousand residents and the basics, and Erlenbach just downstream is a bigger town with more choice for fuel and shopping. Wineries offer tastings and sometimes seasonal taverns, and bakeries and cafés line the small main streets.
Come in early autumn when the vineyards turn colour and the new wine appears in the taverns, or in spring when the hills are fresh. The red sandstone glows in the low sun, and the river slides past with barges heading toward Frankfurt. Stand by the water and imagine Roman soldiers watching the far bank for trouble, with the river as their moat and the forest beyond as the unknown.