Sponsianus

Sponsianus, also known in English as Sponsian, may have been a Roman usurper during the third century. His existence is implied by a series of coins bearing his name, ostensibly part of a hoard excavated in the eighteenth century. No corresponding figure named Sponsianus is mentioned in any ancient sources, and the coins are widely believed to be the work of modern forgers. However, a study of wear marks on the coins published in November 2022 concluded that the coins were authentic, supporting Sponsian's existence as a historical figure. The study's methodology and conclusions have been criticized by a number of scholars.

If there had been a historical Sponsianus, he might have been active during the Crisis of the Third Century, most likely in the province of Dacia. He could have proclaimed himself emperor in the 260s, after Dacia was cut off from the rest of the Empire during the reign of Gallienus. Another possibility is that he was active earlier, during the reign of Philip the Arab or his son, Philip II.