Between 1989 and 1991, Michaelerplatz was subjected to major archaeological excavation and research. Medieval and modern remains were uncovered, also the remains of the Roman canabae, the urban settlement around the fortress.
The canabae served as the residential settlement for the soldiers’ wives and children. Officially, the Roman legionary was not permitted to marry until the third century AD. He usually followed the custom and cohabited with his partner. He spent his leisure hours with his family in the canabae, where he could also find shops, taverns, and frequently brothels.
After the end of the first century AD two road routes led across the Kohlmarkt and Michaelerplatz. This was the junction of the amber route, which came from the region around Aquae (Baden bei Wien), with the Limes, the road following the Danube.
The remains of four different buildings were discovered at the road junction, probably timber-frame. The buildings were inhabited until into the fifth century and occasionally reconstructed as time went by. The building situated east of the junction is known to have had a vestibule, into which subsequently a shop stall was built. It had underfloor and wall heating and was decorated with frescoes, as seen in the small vestiges of a fresco with vine-scroll ornamentation. A foundation stone was found west of the road junction indicating the existence here of a pillar-type commemorative tomb or monument.
Nothing is known about the end of the settlement around the legionary fortress. It was probably destroyed for the first time during the wars against the Marcomanni and Quadi (168 –180 AD).
The end of settlement cannot be dated exactly; the top Roman strata were probably removed to build the medieval Witmarkt (later Kohlmarkt).
The complex was designed for exhibition in 1991 by the renowned Austrian architect Hans Hollein.