Regensburg exists because of a decision made in the year 179. The emperor Marcus Aurelius was fighting the Marcomanni and other tribes across the Danube, and a new legionary fortress was needed on the northern frontier of the province of Raetia. The site chosen was a bluff on the south bank of the Danube, near the point where the river Regen comes in from the north. The fortress was named Castra Regina, the camp by the Regen, and the Third Italic Legion, raised by Marcus Aurelius himself, was stationed there.
The camp was large, a rectangle of about five hundred and forty by four hundred and fifty metres, with stone walls, towers and four gates. Inside were barracks, a headquarters building, a hospital, baths and workshops, and thousands of soldiers lived within its walls. Outside, a civilian settlement of traders, craftsmen and families grew up, and in time the whole complex became the centre of a thriving town. The outline of the camp is still visible in the street plan of the old city, and some Roman stones survive in later buildings.
The old town of Regensburg, with its medieval bridge, cathedral and merchants' towers, is one of the best-preserved in Germany, and UNESCO listed it in 2006. The Danube Limes, of which Castra Regina was a part, was listed in 2021. The city has about a hundred and thirty thousand people, and Reinhausen, across the river, is a suburb. Fuel and food are easy to find, and the old town is a fine place for a long lunch.
For riders, Regensburg is a gateway between the Danube valley and the hills of Bavaria. East of the city, the Danube gives way to the Bavarian Forest, with quiet roads that wind through spruce woods, and west, the Altmuhl valley offers fine riding too. In the city itself, the old town is compact and cobbled, so park the bike on the edge and walk. Early autumn is a lovely time to come, when the light is golden and the evenings are warm.