lixae: were camp followers, mainly slaves, forming part of an army on campaign.

Lugdunum: Lyons in France.

medicus: an army medical orderly or junior physician.

musculus: a mobile covered shed employed in sieges to protect soldiers as they got closer to the enemy wall. The name meant ‘little mouse’, so presumably began as a nickname.

omnes ad stercus: a duty roster of the first century AD from a century of a legion stationed in Egypt has some soldiers assigned ad stercus, literally to the ‘dung’ or ‘shit’. This probably meant a fatigue party cleaning the latrines – or just possibly mucking out the stables. From this I have invented omnes ad stercus as ‘everyone to the latrines’ or ‘we’re all in the shit’.

optio: the second in command of a century of eighty men and deputy to a centurion.

Osrhoene: kingdom on the left bank of the Euphrates with its capital at Edessa which emerged in the break-up of the Seleucid empire. Its kings owed loyalty to the Parthian king of kings, but also maintained friendly relations with Rome. Most of the time, neither side intervened in its domestic affairs.

pilum: the heavy javelin carried by Roman legionaries. It was about 6 to 7 feet long. The shaft was wooden, topped by a slim iron shank ending in a pyramid-shaped point (much like the bodkin arrow used by longbowmen). The shank was not meant to bend. Instead the aim was to concentrate all of the weapon’s considerable weight behind the head so that it would punch through armour or shield. If it hit a shield, the head would go through, and the long iron shank gave it the reach to continue and strike the man behind. Its effective range was probably some 15 to16 yards.

praesidium: the term meant ‘garrison’, and could be employed for a small outpost or a full-sized fort.

prefect (praefectus): the commander of most auxiliary units was called a prefect (although a few unit COs held the title tribune). These were equestrians, who first commanded a cohort of auxiliary infantry, then served as equestrian tribune in a legion, before going on to command a cavalry ala. There was also a praefectus castrorum, or ‘prefect of the camp’, who after the legate – and depending on opinion the broad-stripe senatorial tribune – was next in command of the legion.

primus pilus: the senior centurion out of 59 or 60 in a legion. This was a post of immense prestige, usually held for a single year. Afterwards men automatically gained equestrian status and some went on to higher posts in imperial service.

princeps: the emperor was supposed to be merely the first citizen, and first senator or princeps rather than a monarch.

princeps posterior: the third most senior centurion in the prestigious first cohort of a legion.

procurator: an imperial official who oversaw the tax and financial administration of a province. Although junior to a legate, a procurator reported directly to the emperor.

pugio: the Roman army dagger. There is little evidence for its use by auxiliaries in this era.