Out here on the eastern rim of the Wetterau, between Altenstadt, Hammersbach and the Büdingen forest, the Roman frontier did something unusual. Having come over the Taunus and swung north around the fertile plain, the Limes turned and ran almost due south towards the Main, enclosing the Wetterau like a hand cupped around something precious. The towers numbered WP 4/82 to 5/8, along with small fortlets, guarded this eastern flank, and their remains lie in fields and woodland edges where only a shallow bank or a marker stone gives them away.
Why bother with such a bulge in the frontier? Because the Wetterau was worth it. Its deep loess soils are among the best farmland in Germany, and Rome wanted the grain to feed the garrisons along the Rhine. Altenstadt itself had a fort, and the village of Marköbel in Hammersbach sat right on the line. Long before the legions came, the Celts had already made this landscape their own: seven kilometres away at the Glauberg, archaeologists found a princely burial and a life-size sandstone warrior statue from around 500 BC, now displayed in a striking museum on the hillside. If you only make one detour around here, make it that one.
The riding is open and easy. Roads run across a wide, slightly rolling plain of wheat, rapeseed and orchards, with villages every few kilometres and long sightlines that let you see traffic coming. It is not a place for knee-down cornering. It is a place for steady, contemplative miles with the Vogelsberg rising as a blue dome to the north-east, and the forested hills of the Büdinger Wald offering a few twisting kilometres if you want them. Wind sweeps the plain freely, and in high summer the heat shimmers off the fields, so mornings are kinder.
Altenstadt, three kilometres away, is a town of twelve thousand with fuel, bakeries and supermarkets, so there is no need to plan supplies carefully. Büdingen, a little further north-east, is worth the ride for its astonishingly intact half-timbered old town and walls. Late in the day the low light rakes across the plain and picks out every ripple in the land, which is exactly when old banks and ditches become visible. Walk a few hundred metres along the marked Limes path at that hour and the frontier almost reappears.