The Heidentor is Austria’s best know Roman monument and can be found about 10 minutes walk to the south of the Pertonell Carnuntum amphitheatre. It is all that remains of a much larger edifice built between 354 and 361 AD in honour of Emperor Emperor Constantius II which originally had four huge archways supported by massive pillars. Its size indicates the importance of Carnuntum as an imperial city. The present day name of the building was given to it in the Middle Ages when it was thought to have been the work of heathens.