Augustaion

Originating as a public market, in the 6th century it was transformed into a closed courtyard surrounded by porticoes, and provided the linking space between some of the most important edifices in the Byzantine capital.

His activities included new structures around the Tetrastoon, while the Augustaion was likely carved out of its eastern part at that time, and named after a Porphyry column supporting a statue of his mother, the Augusta Helena.

In its original form, the square was open to the public and functioned as the city's food market (agora), but after Justinian's reconstruction, it became more of an enclosed courtyard where access was restricted.

[1] By the early 15th century however, the Italian traveller Cristoforo Buondelmonti reported that the square lay in ruins, and by the time of Pierre Gilles' sojourn in the 1540s, only the fragments of seven columns remained.

The square was a rectangular open space, enclosed within a colonnaded porticoes (peristyla in Latin, in English peristyles),[3] probably first added in the 459 rebuilding and restored by Justinian.

To its north, the Augustaion was bounded by the Hagia Sophia cathedral and the Patriarchal palace (Patriarcheion), to its east by one of the two Senate houses of the city, built by Constantine or Julian (r. 360–363) and rebuilt by Justinian with a porch of six great columns adorning its front.

The noise and pagan rituals that accompanied the statue's inauguration were criticized by Patriarch John Chrysostom, provoking the Empress' ire and his subsequent deposition and exile.