The reverse of the coin depicts the grandfather of the triumvir, M. Sergius Silanus, a roman hero who lost his right arm in the battles against the Celts, replaced it with an iron prosthesis and continued the fight. Twice captured by the Celts, each time he managed to escape from captivity. We know his fate mainly thanks to Varron's account.
Roman Republic
M. Sergius Silus, Denarius 116-115, Rome mint
Obverse: Head of Roma with winged helmet, mark of value in field
EX SC
Reverse: Helmeted horseman left, holding sword and severed head, Q In field
M SERGI SILVS
Diameter 20 mm, weight 3.95 g