Imperio galo
In AD 260 Postumus made Cologne the capital of the Gallic Empire, which included the Germanic and Gallic provinces, Britannia and the provinces of Hispania. The Gallic Empire lasted only fourteen years. By the 3rd century, only 20,000 people lived in and around the town as the city was badly affected by the crisis of the 3rd century. In AD 310, Emperor Constantine I had a bridge over the Rhine constructed; this was guarded by the "castellum" Divitia (nowadays "Deutz"). In AD 321 Jews are documented in Cologne; when exactly the first Jews arrived in the Rhineland area cannot be established any more, but Cologne's Jewish community claims to be the oldest north of the Alps.