This ala served in Upper Germany until the civil war in AD69, where they were employed by the emperor Vitellius in his futile bid for supremacy. After serving for a short time in Italy, they were shipped to Britain sometime in the seventies, possibly in the train of Petillius Cerialis as early as 71.
“… At Ateste¹ they heard that three cohorts of the Vitellian forces and the squadron of cavalry called Sebosian had occupied Forum Alieni² and built a bridge over the stream there. …” (Tacitus Histories III.vi)
- A city of Venetia in Northern Italy, modern town of Este.
- Possibly Mantua, the modern Legnago, where the bridge would have been over the Adige River.
The first record of this regiment’s service in Britain aside from diplomata is an Agricolan writing tablet from Carlisle. Attested on an inscription recording restoration work on the bathhouse and basilica at Lancaster, during the Gallic empire of Postumous. The early third century altar from Weardale in County Durham which records the hunting exploits of a commander of the unit, may have been placed when on secondment at the nearby Binchester fort, although the unit are known to have been active in the north during the third century, as shown by stamped tiles from Brough-under-Stainmoor.
Evidence for the presence of Ala Augusta Sebosiana in Britain
- Burn 95; CIL XVI.48; military diploma, dated: January 19th AD103.
- Burn 100; CIL XVI.65 military diploma dated: July 17th AD122.
- L’Année Épigraphique 1997.1779a diploma dated c. AD126.
- L’Année Épigraphique 1997.1001 diploma dated 27th February AD158.
- Luguvalium (Carlisle, Cumbria; Britannia xxiii, 1992, p.153; writing-tablet; Agricolan?).
- Calunium (Lancaster, Lancashire; RIB 605; AD262-6).
- ?Verteris (Brough-under-Stainmoor, Cumbria; RIB 2411-89; lead seal).
- ?Vinovium (Weardale, nr. Binchester, Durham; RIB 1041; altar to Silvanus).