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 Church of St Donatus name refers to Donatus of Zadar, who began construction on this church in the 9th century and ended it on the northeastern part of the Roman forum. It is the largest Pre-Romanesque building in Croatia.
The beginning of the building of the church was placed to the second half of the 8th century, and it is supposed to have been completed in the 9th century. The Zadar bishop and diplomat Donat (8th and 9th centuries) is credited with the building of the church. He led the representations of the Dalmatian cities to Constantinople and Charles the Great, which is why this church bears slight resemblance to Charlemagne's court chapels, especially the one in Aachen, and also to the Basilica of San Vitale in Ravenna. It belongs to the Pre-Romanesque architectural period.
The circular church, formerly domed, is 27 m high and is characterised by simplicity and technical primitivism.