
1) Military rank of ancient Rome
Found on
https://www.crosswordclues.com/clue/tesserarius

A tesserarius (tesserārius, from tessera, a small tile or block of wood on which watchwords were written), was a watch commander in the Roman army. They organized and had command over the nightly guard assigned to keep watch over the fort when in garrison or on campaign and were responsible for getting the watchwords from the commander and seeing...
Found on
http://en.wikipedia.org/wiki/Tesserarius

NCO in charge of the watchword.
Found on
http://www.encyclo.co.uk/local/20764

He was a non-commissioned officer in the century, who was mainly responsible for small sentry pickets and fatigue parties, and so had to receive and pass on the daily century watchword each morning. Thought to also be known as the army spy.
Found on
http://www.encyclo.co.uk/visitor-contributions.php
No exact match found.