One of the oldest churches in Istanbul, Haghia Eirene was built by the Emperor Constantine in the 4th century. The Greek name Haghia Eirene means "Divine Peace" and is also the name of a saint who lived in the same century.

The saint, whose real name was Penelope, belonged to a noble Persian family. She was engaged in disseminating the Christian faith among the people, but though the pagans threw her into a well full of snakes, and stoned and dragged her along the ground with their horses they could not kill her. Taking their failure as a sign of a miracle, the pagans finally converted to Christianity. So, that was how Eirene became a saint.

The Emperor Conslantme named this first temple of monotheism Haghia Eirene after the saint. The church is known to have served as the patriarchal cathedral until the completion of Haghia Sophia but, being in the centre of violent disputes between the Arians and the Orthodox party in that period, the wooden building suffered many calamities over the years. During the Nlka Revolt it was burned to the ground but was later rebuilt by the Emperor Justinian.

When the Ottomans, after the conquest of Istanbul, built Topkapi Palace, Haghia Eirene was enclosed within the outer walls of the palace and probably that was why the church was never converted into a mosque. At first, it served as the arsenal of the Janissaries. In the 19th century, upon the decision to use it as a museum, the place was emptied and re-designed as a museum for old Ottoman arms. Many years later the arms were transferred to Harbiye and the church, with its excellent location and acoustics, started to be used as a venue for musical events. Still used for the same purpose, it also serves as an exhibition centre for contemporary arts and Biennials.
The building consists of a narthex, a mam interior with three naves and an apse. As for the material used and the architectural design, it is a typical Byzantine building The transition from a domed basilica to a centralized Greek-cross plan is the main architectural feature of the building. Despite the fact that the atrium was much reduced in size during the Ottoman period, Haghia Eirene is the only surviving church still to possess an atrium. The four-stepped synthronon in the semi -dome symbolizes the Golgotha Hill where Christ was crucified and the cross with black contours symbolizes Jesus Himself. Because of the rise of iconoclasm between 726 and 842, the walls are devoid of any ornament. During the Ottoman period the cross in the dome was concealed under a huge flag. The mosaics in the main interior, which would appear to have almost certainly been made for Constantine the Great, are very early examples of Byzantine art. The installation consisting of an arrangement of the floor mosaics carried out by the famous modern artist llya Kabakov for the 4th Istanbul Biennial in 1995 is still remembered as one of the most impressive works in the exhibition. The right hand section of the upper gallery of Haghia Eirene contains late Byzantine frescoes of saints. All this would seem to suggest that the interior was covered with frescoes, an art form that was widely preferred to mosaics in the late Byzantine period, probably because they were cheaper and easier to apply. (s2)

Though the present church dates only from the 6th century, it is at least the third building to be erected on what is thought to be the oldest site of Christian worship in Istanbul. Within a decade of the Muslim conquest of the city in 1453 it had been included within the Topkapi Palace complex and pressed into use as an arsenal. Today the building, which has
good acoustics, is the setting for concerts during the Istanbul Music Festival .

St. Irene Church for the first time was constnicted over the remains of Afrodite Temple during the early 4th century AD. It took its last form after being restored by Justinian in 532. Before St. Solia was constructed, the second Ecumenical Council was held here in 381.
It kept its importance as being the second largest church after the construction of St. Sofia.
St. Irene Church, with a cross plan, is the only Byzantine church in Istanbul whose atrium has survived. The mosaics of the church have the influence of Iconoclastic period (726-841). The building was used as an arsenal by Ottomans between the 15th - 18th centuries. From 1846 on it served as an Archaeological Museum. Today, St. Irene Church is used for classical music concerts due to its excellent acoustics. You can visit the church only by a permission. (s4)