Optio

In a Roman army an optio (Latin: optiō, from optāre, 'to choose', so-called because superior officers chose the optio; pl.: optiones) held a rank in a centuria (century) similar to that of an executive officer. The main function of an optio was as an optio centuriae, the second-in-command of a century, although there were many other roles an optio could fulfill. Optiones carried out vital roles in the Roman military. An optio was stationed at the rear of the ranks to keep the troops in order. His duties would include enforcing the orders of the centurion, taking over the centurion's command in battle should the need arise, supervising his subordinates, and a variety of administrative duties. Optio pay was double the standard legionary pay and optiones were the most likely candidates to replace the centurion if his position became vacant.