The gallery is laid out in a horseshoe shape that encloses the nave until the apse. Several mosaics are preserved in the upper gallery, an area traditionally reserved for the empress and her court.

Deesis: In Byzantine art, and later Eastern Orthodox art generally, the Deësis or Deisis, is a traditional iconic representation of Christ in Majesty or Christ Pantocrator: enthroned, carrying a book, and flanked by the Virgin Mary and St. John the Baptist, and sometimes other saints and angels. - Wikipedia: Deesis (online Dec. 2014)

"... the marriage between young John Comnenus and the Hungarian Princess Piroska, daughter of King Ladislaus of Hungary, was arranged in order to improve relations between the two countries. It proved a happy marriage: the couple had eight children. ...  the empress has a fair complexion and long blond hair in plaits; the emperor, who was nicknamed the Moor, has a dark complexion. In the centre of the mosaic the portrait of Mary is a rather conventional work." -  Byzantine Heritage - Hagia Sophia (online Dec. 2014)

"The Byzantine court was a dangerous place and emperors were suspicious of everyone and in particular of their relatives. Emperor Constantine VIII (1025-28) was wary of his potential sons-in-law and for this reason he did not allow his three daughters to marry. Only on his deathbed he married his daughter Zoe to his chosen heir Romanos III. Three days later he passed away and Romanos and Zoe succeeded to the throne. She was 50 and her husband paid little attention to her. They were portrayed in a beautiful mosaic in the upper gallery of Hagia Sophia: Zoe looks very humble and very small, but she had an iron will and she resented the behaviour of her husband.

"A few years later Romanos was found dead in his bath and soon after Zoe married her chamberlain who was 24 and who became Emperor Michael IV; his portrait replaced that of Romanos in the mosaic.
Zoe outlived her second husband and she became the co-ruler of his adoptive nephew Michael V. The new emperor tried to banish Zoe, but the people of Constantinople revolted and Michael was arrested, blinded and sent to a monastery where he died soon after.

"Zoe became the sole ruler of the empire and she remarried a third time: the portrait of Constantine IX Monomachos (the one who fights alone) replaced that of Michael IV." -  Byzantine heritage - Hagia Sophia (online Dec. 2014)

"The subject presents a group of two Emperors on either side of the Virgin enthroned with the Infant Savior.  The figures are inscribed with their name and titles.  In the center the Virgin with her appellation of Mother of God.  To our right, Constantine the Great as a saint;  to our left, Justinian the First; both emperors are nimbate with halos.  The Virgin holds the Infant in her lap.  Constantine carries the City that bares his name.  Justinian supports in his hands the Church of St. Sophia.  The green ground beneath the figures is presented in four horizontal layers which grow darker as they recede.  The background is bright gold mosaic which vibrates with every pulse of light and creating an air of celestial brilliance around the amethyst-blue figures.  The mosaic is ragged along its edges; originally it was surrounded by a border of red tessellate, of which parts remain; at the base of the picture no less than eleven rows are missing.  - Bob Atchison: Hagia Sophia (online Dec. 2014)

"The Child is represented seated on the knees of the Virgin.  He is blessing with the right hand in the manner of the Eastern Orthodox Church, the tip of the third finger touching the thumb.  In the left hand he holds a scroll. ... The large dark reddish-brown pupils give depth to the expression.  ...  The mouth breaks gently into a smile.  The general impression is that of a face filled with thoughtful alertness and radiance and the whole figure seems ablaze with light.  At the same time we are aware that the artist in his characteristic Byzantine pre-occupation to endow the Child with the miraculous attributes has assigned to the body of an infant the head of an adolescent.

"Around the head of the Child is a cruciform nimbus.  There is some Fossati restoration in it.  The hand of the child is unduly large when compared with the other limbs of the body.  The artist has done this to emphasize the benediction.  The bare right foot is large in comparison with the body of the Child.  The left foot is less visible and was partially destroyed by a bad Fosatti restoration which is very distracting since the foot is missing toes." -  Bob Atchison: Hagia Sophia (online Dec. 2014)