Roman Coin - Coin of Antoninus representing Italy

The letters TR. POT. an abbreviation of "Tribunitia Potestas," signify the tribune power with which  the Emperors were invested ; the letters cos. III. mean that Antoninus was, or had been, Consul for the third time; and s.c. that it was by order of the Senate, "Senatus-Consulto," that the piece of money was coined. Antoninus having had his third Consulship in AD 140. and the fourth in 145, the medal is either of that year or one of the four following. The Senate of the Empire only coined bronze money. The first trib. pot. dated from the day of the prince's accession; since Trajan's time, all the succeeding ones dated from the 1st of January. Hence the number of the trib. pot. gives the number of the years of the reign.