On July 26th we commemorate the Synaxis of our Most Holy Lady the Theotokos in Pagidion next to the New Colonnade.
According to the Chronicle of John Malalas, during the reign of Emperor Leo I the Thracian, in the year 469, there was "a great conflagration in Constantinople, such as had never been experienced before. The flames spread from sea to sea, and the emperor Leo, fearing for the palace, left the city and crossed over to Saint Mamas. He spent six months there on a processus. He built a harbor there and a colonnade, which he called the New Colonnade, as it is called to the present day."
From this we gather that the New Colonnade was near the quarter of Constantinople called Saint Mamas, which was on the European side of the Bosphorus, outside of Galata, at the northern part of the Golden Horn mouth. And from this we also know that next to it was Pagidion. It was perhaps during the reign of the same Emperor Leo I that a church or monastery dedicated to the Theotokos was built there, whose Synaxis was celebrated on July 26th.