This may be a Christian cross (I think it is). If so, it is the first Christian cross on a Roman coin. 20-19 mm. Struck 316 RIC Ticinum 45 SOLI INVICTO COMITI, cross in field left, * in field right, PT in exergue. Please compare with prices elsewhere. [$65, reduced to $55 + $4 in the US. $3 more abroad] I have more coins and coin-books for sale at: http://augustuscoins.com/index.html If you want to know about early Christian symbolism on ancient coins, there are good websites, my own among them: http://augustuscoins.com/ed/Christian/ChristianSymbols.html and Victor Clark has another: http://www.constantinethegreatcoins.com/symbols/