218 AD., Macrinus, Rome mint, Æ As, RIC 152.

Macrinus, Rome mint, January 218 AD.,
Æ As (24-26 mm / 9,90 g),
Obv.: IMP CAES M OPEL SEV MACRINVS AVG, laureate, cuirassed bust of Macrinus right, seen from front, with medium to long beard.
Rev.: PONTIF MAX TR P - II / [COS] II P P / S - C, emperor holding branch and eagle-tipped scepter in quadriga left, crowned by Victory standing behind him. RIC IV, II, 18, 152 .

Rare and historical.
This type commemorates the consulship that Macrinus assumed on 1 January 218 while still absent in Syria. The legend calls Macrinus COS II, but this was an error: the emperor had decided to content himself with the title COS in 218, but the mint had not yet learned of his decision.
See Curtis Clay, "Coinage of Macrinus", Numismatische Zeitschrift 93 (1979).