The original mosaics in Hagia Sophia were completed in the 6th century. Unfortunately, they were all destroyed during the periods of Byzantine Iconoclasm, when religious images were forbidden by leaders of the Eastern Church. The current mosaics were made between 867 and the 14th century.
The first mosaic you’ll likely spot is in the lower gallery near the entry. As you enter Hagia Sophia through the narthex, you’ll walk through a gigantic door called the Imperial Gate. Above the door is the Mosaic of the Imperial Gate, which was completed in the late 9th century. It depicts either Byzantine Emperor Leo VI or his son, Constantine VII Porphyrogenitus, kneeling before Christ. Archangel Gabriel and the Virgin Mary are on the sides. On the Bible is written “May peace be with you. I am the Divine Light.”
Once inside the naos (the main part of the church, four Seraphim (six-winged angel) mosaics sit on the corners near the dome. They date back to the 14th century and were rediscovered by the Fossati brothers during the 1847 renovations, after being covered by metallic lids since Hagia Sophia was converted to a mosque. The angels on the east are originals while the angels on the west were recreated as frescoes by the Fossatis.
Above the altar is the apse, with a mosaic of the Virgin and Child. This mosaic is very important because it was the very first one created after iconoclasm. It was unveiled on March 29, 867, by Patriarch Photios I and Emperors Michael III and Basil I.
On the upper walls on the north side are niches with mosaics of some of the most important church fathers. Unfortunately, due to earthquakes, only three survive in good condition. They depict St. John Chrysostom, St. Ignatius Theophoros, and St. Ignatios the Younger and are best seen from the southern side of the upper gallery.
The southern half of the upper gallery is home to most of the Byzantine mosaics in Hagia Sophia. The mosaics have been under restoration since the 1930s and more are being uncovered over the years.
The first one is just inside the marble door. It’s called the Deësis (‘Δέησις) and was probably made in 1261. It depicts Christ Pantocrator with the Virgin Mary to his left and St. John the Baptist to his right. They are praying to Christ for the mercy of the people during doomsday. The mosaic is incomplete, but a small picture of a complete version is on display to show what it may have looked like.
At the southeast end are a few mosaics featuring Byzantine Emperors and Empresses with religious figures. The Komnenos mosaic dates back to 1122 depicts Emperor Ioannis II Komnenos, the Virgin and Child, and Empress Irene. Ioannis II Komnenos is shown holding a purse, which indicates a large imperial donation to the church. Irene, who was of Hungarian origin and the daughter of King László of Hungary, is shown with long braided red hair and rosy cheeks. Their son Alexios Komnenos, who was coronated as co-emperor with his father at the age of 17, is displayed on a side panel to the right.
The Zoe mosaic features Christ Pantocrator with Empress Zoe Porphyrogenita and her third husband, Constantine IX Monomachos. Constantine IX Monomachos is holding a purse, indicating a large imperial donation to the church, while Zoe Porphyrogenita is holding a scroll, indicating donations she made. The inscription above the Emperor says “Constantine, pious emperor in Christ the God, king of the Romans, Monomachus”. The inscription above the Empress says “Zoe, the very pious Augusta”. The heads are not original to the bodies and there are two theories why. One is that they were made for an earlier emperor and empress and changed for Zoe. Another is that they originally depicted Zoe’s first husband, Romanos III Argyros, or her second husband, Michael IV, and changed it to show Constantine IX.
The mosaic of Emperor Alexander is a little hard to find. It’s hidden away in a blind corner near the other mosaics. It depicts Alexander, who ruled for 13 months and died after a game of tzykanion (polo) on June 6, 913. The mosaic dates back to the 10th century and is one of the best-preserved in Hagia Sophia. Rather than being plastered over like the rest, this one was painted over.
The upper gallery is also the best place to spot the mosaics of Archangels Gabriel and Michael in the apse. The Michael mosaic on the left is largely destroyed with only his foot and part of a wing remaining. The Gabriel mosaic on the right is in much better condition.
Finally, when exiting Hagia Sophia through the southwest vestibule, pay attention to the mirror above the exit door. When you turn around, you’ll be looking at one of the best-preserved mosaics in the building. Dating back to the 10th century, it was discovered by the Fossati brothers in 1849 and features the Virgin and Child in the center. To the left is Justinian I presenting a model of Hagia Sophia and the inscription “Famous Emperor Justinian”. To the right is Constantine presenting a model of his city and the inscription “Among the saints is great Emperor Constantine”.