sacramentum: the military oath taken by soldiers when they joined the army and renewed periodically, especially on the accession of a new emperor. Obedience and loyalty was sworn to the state and the emperor.

Saka: a nomadic people from the Steppes, who were believed to be kin – or at least similar in culture, lifestyle and style of warfare – to the Sarmatians. At times they fought against the Parthians, but also were frequently recruited by them.

scorpion (scorpio, pl. scorpiones): a light torsion catapult or ballista with a superficial resemblance to a large crossbow. They shot a heavy bolt with considerable accuracy and tremendous force to a range beyond bowshot. Julius Caesar describes a bolt from one of these engines going through the leg of an enemy cavalryman and pinning him to the saddle.

seplasiarius (or seplasiario): military pharmascist working in a fort’s hospital.

signifer: a standard-bearer, specifically one carrying a century’s standard or signum (pl. signa).

Silures: a tribe or people occupying what is now South Wales. They fought a long campaign before being overrun by the Romans. Tacitus described them as having curly hair and darker hair or complexions than other Britons, and suggested that they looked more like Spaniards (although since he misunderstood the geography of Britain he also believed that their homeland was closer to Spain than Gaul).

spatha: another Latin term for sword, which is now conventional to employ for the longer blades used mainly by horsemen in this period.

stationarii: soldiers detached from their parent units and stationed as garrison elsewhere, often in a small outpost.

Strategos (pl. Strategoi): originally a name for a general or senior army officer, in most Greek city-states these were elected posts. Over time, many evolved to take on civil responsibilities, especially when actual warfare became less and less common.

tesserarius: the third in command of a century after the optio and signifer, the title originally came from their responsibility for overseeing sentries. The watchword for each night was written on a tessera or tablet.

thetatus: in some Roman army documents, the death of a soldier was indicated by the Greek letter theta. From this came the slang word thetatus, meaning dead.

tribune: each legion had six tribunes. The most senior was the broad-stripe tribune (tribunus laticlavius), who was a young aristocrat at an early stage of a senatorial career. Such men were usually in their late teens or very early twenties. There were also five narrow-stripe or junior tribunes (tribuni angusticlavii).

Triclina: the three couches arranged in a u-shape at a formal Roman dinner party. The open end was to permit the dishes to be brought in and replaced for each course.

Zeugma: major city and legionary base in the old kingdom of Commagene. It guarded one of the most important crossing places on the Euphrates.

CAST OF CHARACTERS

Names with an asterisk (*) are real, though their characters have been embellished for the story. Appearance in other novels is noted as follows:

V = Vindolanda

ES = The Encircling Sea