The Germanic confederation of the Alemanni attempted to cross the Rhine several times in the 4th century, but were repelled, one such event being the Battle of Solicinium (368).However, in the great invasion of AD 406, the Alemanni appear to have crossed the Rhine river a final time, conquering and then settling what is today Alsace and a large part of the Swiss Plateau.The Bishop also allowed the furriers to establish a guild in 1226.Eventually about 15 guilds were established in the 13th century.The bridge was largely funded by Basel's Jewish community which had settled there a century earlier.For many centuries to come Basel possessed the only permanent bridge over the river "between Lake Constance and the sea".In 1412 (or earlier), the well-known guesthouse Zum Goldenen Sternen was established.
The University of Basel, founded in 1460, Switzerland's oldest university and the city's centuries long commitment to humanism, have made Basel a safe haven during times of political unrest in other parts of Europe to the likes of Erasmus of Rotterdam, the Holbein family, and more recently also to Hermann Hesse and Karl Jaspers.
In AD 83, Basel was incorporated into the Roman province of Germania Superior.
Roman control over the area deteriorated in the 3rd century, and Basel became an outpost of the Provincia Maxima Sequanorum formed by Diocletian.
The council then forbade Jews in Basel for 200 years, except that their money was helpful in rebuilding after the Basel earthquake of 1356 which destroyed much of the city along with a number of castles in the vicinity.
The city offered courts to nobles as an alternative to rebuilding their castles, in exchange for the nobles' military protection of the city.