The Twenty-Second Legion comprised some five and a half thousand men. The basic unit was the century of eighty men commanded by a centurion with an optio acting as second in command. The century was divided into eight-man sections which shared a room together in barracks and a tent when on campaign. Six centuries made up a cohort, and ten cohorts made up a legion, with the first cohort being double-size. Each legion was accompanied by a cavalry unit of one hundred and twenty men, divided into four squadrons, who served as scouts and messengers. In descending order the main ranks were as follows:

The legate was a man from an equestrian rather than a senatorial background, as was the case with legions outside Egypt. The legate would command the legion for several years and hope to make something of a name for himself in order to enhance his subsequent political career.

The camp prefect was a veteran who would previously have been the chief centurion of the legion and was at the summit of a professional soldier’s career.

Six tribunes served as staff officers. These would be men in their early twenties serving in the army for the first time to gain administrative experience before taking up junior posts in civil administration. The senior tribune was different. He was destined for high political office and eventual command of a legion.

Sixty centurions provided the disciplinary and training backbone of the legion. They were hand-picked for their command qualities. The most senior centurion commanded the First Century of the First Cohort.

The four decurions of the legion commanded the cavalry squadrons and hoped for promotion to the command of auxiliary cavalry units.

Each centurion was assisted by an optio who would act as an orderly, with minor command duties. Optios would be waiting for a vacancy in the centurionate.

Below the optios were the legionaries, men who had signed on for twenty-five years. In theory, a man had to be a Roman citizen to qualify for enlistment, but recruits were increasingly drawn from local populations and given Roman citizenship on joining the legions.

Lower in status than the legionaries were the men of the auxiliary cohorts. These were recruited from the provinces and provided the Roman Empire with its cavalry, light infantry and other specialist skills. Roman citizenship was awarded on completion of twenty-five years of service.

The Imperial Roman Navy

The Romans came to naval warfare rather late in the day and it was not until the reign of Augustus (27 BC—14 AD) that they established a standing navy. The main strength was divided into two fleets, based at Misenum and Ravenna, with smaller fleets based in Alexandria and other large ports around the Mediterranean. As well as keeping the peace at sea, the navy was tasked with patrolling the great rivers of the Empire such as the Rhine, the Danube and, of course, the Nile.