A Centurion (Latin: centurio; Greek: κεντυρίων, kentyríōn, or ἑκατόνταρχος, hekatóntarkhos) was a professional officer of the Roman army after the Marian reforms of 107 BC. Most centurions commanded groups of centuries of around 80 legionaries, but senior centurions commanded cohorts or took senior staff roles in their legion. Centurions were also found in the Roman navy. Their symbol of office was the vine staff, with which they disciplined even Roman citizens protected from other forms of beating by the Porcian Laws.
Centurion on Wikipedia