From NC :

 

The Church of St. Irina is one of the first basilica temples of the apostolic Christianity, which replaced the former circus temples of patrimonial Christianity

Today we all know well that the altars of Christian churches are directed to the east. It must be said that for many old temples this direction is not exactly consistent, since earlier the east was determined not by compass, but by the sun. Nevertheless, deviations from the eastern direction, which are observed for Christian churches, are relatively small. As a rule, they do not exceed 15 degrees.

For example, the altar of the Grand Hagia Sophia in Istanbul is facing east. Deviation from the strictly east direction is only a few degrees. The same applies to most other Christian churches in Istanbul.

However, there are exceptions. The most striking of them is the temple of St. Irina, built, as it is believed, by Constantine the Great himself. In other words, the temple of St. Irina is the first or one of the very first Christian temples in Istanbul. Indeed, it was under Constantine the Great who built this temple that Christianity was adopted in the Roman Empire, and the capital of the Empire was moved to a new place – in the city of Constantinople, aka Istanbul.

 

Fascinating.

4th/5th or 14th/15th cc?

:o)