Second largest church of the Eastern Roman Empire, following Hagia Sophia, Hagia Eirene was built on top of an older temple, out of wood. The Nica riot, occurred during the rule of Emperor Justinianus on 532 caused both Hagia Sophia and Hagia Eirene to burn down, and both these churches has been rebuilt following these incidents. Hagia Eirene means “Holy Peace” Consisting of three sections, naos narthex and atrium, Hagia Eirene is the only surviving example of a Byzantine period church today with a standing atrium. Built as a basilica with three naves during the reign of Constantinos the Great (306–337), it has been repaired by Leo III (717–741) and his son Constantine Copronymus (741–775) following the damages caused by the great earthquake of 740. Its upper structure was completely renovated and the building gained its appearance as known today as a domed church with basilical plan. The decoration of the structure, might have been richly decorated with figurative ornaments during the reign of Justinianus (527–565) but, it has been completely changed during the repairs of Leo III and Constantine Copronymus who both are emperors of the Iconoclastic era. The cross depiction that can be seen today on its half dome has been made during that time. Only a few modifications has been made during the Ottoman period, since Hagia Eirene has not been converted into a mosque following the conquest of Constantinople. With the building of Topkapi Palace, the church became located in the Palace garden grounds, and has been transformed into an armory. Since it is located inside Palace grounds, it’s been known as “Enderun Cebehanesi” or “İç Cebehane” meaning “inner arsenal”. Two Epigraphs are located on top of the main entrance of Hagia Eirene, which are still in situ today. One of those is placed there in 1726, with the organization of Dar-ül Esliha (House of Weapons). With this organization, a throne room has been built in the atrium for the Sultans to use during their visits. This throne room has reached today with the ornaments crafted by Krikor Amira Balyan during the reign of Mahmud II. The second epigraph recounts the renovations performed in 1744, during the reign of Mahmud I. The portico located in front of the entrance gate has been built in that location during these renovations. Being used as an army warehouse, in the year 1846, two parallel exhibitions had been organized on two sides of the atrium named “Mecma-i Asar-ı Atika” (Archaeological Artifacts Collection) and “Mecma-i Esliha-i Atika (Ancient Weapons Collection). Based on the archaeological artefacts collection in 1869, Hagia Eirene was named the first official museum of the Ottoman Empire, named “Müze-i Hümâyûn”. In 1875, the archaeological artifacts were moved to the new museum established in Çinili Köşk (Tiled Kiosk). In the years before the 1st World War, the weapons collection in Hagia Eirene has been reorganized and the building had been reorganized as the first Military Museum. The building served this purpose until 1930, into the Republic era. Subordinated into the Hagia Sophia Museum Directorate in 1949, the Hagia Eirene Monument was opened for visitors in January 9th, 2014 as a section under Topkapı Palace Museum Directorate.