321 AD., Constantinus I., Rome mint, Follis, RIC 237.
Constantinus I. (Constantine), Rome mint, officina 1, 321 AD.,
Æ Follis (18-19 mm / 3,04 g),
Obv.: CONSTAN - TINVS AVG , laureate head of Constantinus right.
Rev.: D N CONSTANTINI MAX AVG / VOT / XX // R P , wreath around VOT / XX , R P in exergue.
RIC VII, 321, 237 (C3) .
thanks to Victor Clark for more details ( http://www.forumancientcoins.com/board/index.php?topic=67237 )