The name Sponsianus is an authentic, but exceedingly rare, Roman name, derived from the Latin word spondere, to solemnly promise.Marcus Terentius Varro, De Lingua Latina (On the Latin Language), vi. 70 ff.; Charlton T. Lewis and Charles Short, A Latin Dictionary, Clarendon Press, Oxford (1879). Pearson notes only one instance, from a funerary inscription naming an obscure person called Nicodemus Sponsianus, dating from the early first century.. This inscription was not published until 1726, several years after the supposed discovery of Sponsian's coins, and Pearson regards this as an argument for their authenticity: a forger would not have known of the name. Two other instances appear in the Corpus Inscriptionum Latinarum, a catalogue of known Latin inscriptions, all dating from the same period,, . while a further two inscriptions give the abbreviated form Sposianus;, . all five inscriptions are from Rome. One of the latter was published by Jan Gruter well before the first known appearance of the coins,Jan Gruter, Inscriptiones Antiquae Totius Orbis Romani (Ancient Inscriptions from the Whole Roman World), Heidelberg (1603), p. 581. and other examples are known besides these, so a forger might still have been aware of or guessed at the existence of such a name.[https://books.google.com/books?id=GaY3AAAAIAAJ&dq=sposianus+lamp&pg=PA42 H. Williams, Kenchreai: Eastern Port of Corinth, E. J. Brill, Leiden (1981), vol. V, p. 42.
