As in many of the region’s towns, Oberwesel quite possibly had its beginnings as a Celtic settlement, named "Vosavia" or "Volsolvia". The Romans later maintained a horse-changing station with a hostel here. After the fall of the limes, Oberwesel became a Frankish royal holding with a royal estate. The Wesel Estate passed under Emperor Otto I in 966 to the Archbishopric of Magdeburg. In 1220, Emperor Frederick II dissolved the pledge and Oberwesel became a free imperial city. In 1255, Oberwesel became a member of the Rhenish League of Towns ("Rheinischer Städtebund"), but in 1309, it lost its status as a free imperial city and fell under the lordship of the Electorate of Trier, to which it belonged until Secularization after the French Revolutionary Wars in 1802. In the so-called "Weseler Krieg" (“Wesel War”) in 1390 and 1391, the town tried yet again to turn over a new leaf, but after a successful siege by Archbishop of Trier Werner von Falkenstein, it had to back down.