optio

thumb|Roman optio in a re-enactment at Cilurnum|Chesters Fort in May 2000

In a Roman army an '''''' (, from , 'to choose', so-called because superior officers chose the ; : ) held a rank in a (century) similar to that of an executive officer. The main function of an was as an , the second-in-command of a century, although there were many other roles an could fulfill.