Originally built as an agora and named as Tetrastoon (because of the four columns) by Septimus Severus, Augustaion would be used on ceremonial occasions and later as a forecourt of Hagia Sophia. This rectangular court was in front of Hagia Sophia. It was between the Chalke (the entrance of the Great Palace) and Mese (Divanyolu).
The Million stone which is thought to be the starting point in the world was outside on the Ausgustaion. In the southwest corner of it, there was a 50 meter high bronze sheated column which would carry the statue of Justinian (column of Justinian) holding a globe on one hand and pointing the east with other hand.
The square was full of statues of the Emperors like Justinian and Theodosius. There was also a statue of Augusta Helena by whose name Augustaion was named after.