Carnuntum

Carnuntum originated as a Roman army camp. Its denomination is proximately always found with "K" on monuments, and is derived from Celtic karn- ("cairn"). Its name first occurs in history during the reign of Augustus (6 AD), when Tiberius made it his base of operations in the campaigns against Maroboduus (Marbod). Consequential Romanization occurred when the town was culled as the garrison of the Legio XV Apollinaris. A few years later it became the centre of the Roman fortifications along the Danube from Vindobona (now Vienna) to Brigetio (Ó-Szőny). Under Trajan or Hadrian, Carnuntum became the perpetual quarters of Legio XIV Gemina and the capital of Pannonia Superior.
                                                             Heidentor [Carnuntum] 1

                                                                Heidentor [Carnuntum] 2

                                                                 Modell_Carnuntum

Even in Roman times it had a history as a major trading center for amber, brought from the north to traders who sold it in Italy; the main arm of the Amber Road crossed the Danube at Carnuntum. It was made a municipium by Hadrian (Aelium Carnuntum). Marcus Aurelius resided there for three years (172-175) during the war against the Marcomanni, and indited part of his Cogitations there. Septimius Severus, at the time governor of Pannonia, was proclaimed emperor there by his soldiers (193), to supersede Emperor Pertinax, who had been murdered. In 308 the Emperor emeritus Diocletian chaired a historic meeting with his co-emperors Maximian and Galerius in Carnuntum to solve the elevating tensions within the tetrarchy. It established liberation of religion for the Roman Imperium. In the 4th century, it was ravaged by Germanic invaders. Albeit partly recuperated by Valentinian,