TOLBIACUM in North Gallia, on the road from Augusta Trevirorum ( Trier) to Colonia Agrippina ( Cologne). The distance of Tolbiacum from Colonia is xvi. in the Antonine Itin. Tolbiacum is Zülpich, south-west of Bonn, on the direct road from Trierto Cologne. The words vicus supernorumor vicus supenorum,which occur in the MSS. of the Itin. after the name Tolbiaco,have not been explained. Several writers have proposed to alter them. Tacitus (Tac. Hist. 4.79) places Tolbiacum within the limits of the territory of the Agrippinenses or the Colonia Agrippina.
[G.L]