Marcus Silbannacus was a usurper during the reign of Philip I. History has not been kind to Silbannacus since it has failed to record his existence. Silbannacus is known only from a single coin that now resides in the British Museum. Silbannacus most likely led a very short-lived rebellion around 248 AD on the Rhine perhaps about the same time period as Pacatian in the Balkins. He was most likely killed by his own troops since there is no record of a confrontation between himself and Philip I.
Silbannacus appears to predate another usurper Sponsianus by perhaps no more than one year. Silbannacus appears to have defended the region against the Germanic Alamanni during the first half of 244 AD. His coinage declares a victory as well as a usurpation of power with the support of the Senate. It is possible that Sponsianus may have been Severus Hostilianus of the Byzantine sources which may have confused him with Hostilian (251AD), the young son of Trajan Decius (249-251AD). Consequently, Sponsianus may be the same person noted by his Zonaras who refers to Severos Stilianos.
It may have been the usurpation of Marcus Silbannacus and his support by the Senate that forced Philip to make concessions to the Persians.
IMP MAR SILBANNACVS AVG
Note: The style of this unique coin and its fabric places its time of mintage to the reign of Philip I.
AR Antoninianus (unique)
Monetary History of the World
©Martin A. Armstrong