Abusina or Abusena was a Roman castra (military outpost), and later of town, of the Roman Province of Raetia.
It was at Eining near Abensberg, on the Upper German- Raetian Limes , which at this point was the Danube River. Abusina stood near to the eastern termination of the high road which ran from the Roman military station Vindonissa on the Aar to the Danube.
In the 2nd century the fort was occupied by the Cohors IV Tungrorum with about 1,000 men. By the later Roman Empire, archaeology and the Notitia Dignitatum suggest the site was occupied by Cohors III Brittonum with only 50 men.
References:The historical centre of Briançon is a strongly fortified town, built by Vauban to defend the region from Austrians in the 17th century. Its streets are very steep and narrow, though picturesque. Briançon lies at the foot of the descent from the Col de Montgenèvre, giving access to Turin, so a great number of other fortifications have been constructed on the surrounding heights, especially towards the east.
The Savoyards made two raids into French territory in 1691 and 1692. As a result, Vauban was dispatched to inspect the frontier defences, which had been ill-equiped to deal with the attack from Savoy. He returned to the area in 1700 to check on the progress that had been made since his first visit. When Vauban visited Briançon, work on the defences had already started under a local engineer, Monsieur d"Angrogne in 1692.