Carnuntum was a major Roman legionary fortress on the Danube in Lower Austria, midway between Vienna and Bratislava. Established under Emperor Claudius around AD 50, it became capital of Pannonia Superior in AD 106 and grew to a city of some 50,000 inhabitants. Marcus Aurelius wrote part of his Meditations here during campaigns against the Marcomanni (172-174). Septimius Severus was proclaimed emperor at Carnuntum in AD 193. The 10 km-squared archaeological park preserves reconstructed Roman quarters, palace ruins, two amphitheatres, and the Heidentor triumphal arch.
Archaeological Park Carnuntum

| Type | Fortress/citadel |
|---|---|
| Period | 1 - 500 AD |
| Country | Austria |
| Coordinates | 48.1168° N, 16.8667° E |
Austria