Which original decorations of Hagia Sophia have survived from the Byzantine period?

Several original architectural and decorative elements from the Byzantine period have survived within the Hagia Sophia, despite the loss of much of its initial ornamentation.

The surviving original features include:

• Structural Elements: The building’s marble columns, which were selected for their variety and color, remain intact. Additionally, the elaborately carved cornices and capitals have survived.1
• Wall Coverings: The lower sections of the walls are still covered with their original marble slabs.1
• Mosaics: While most of the original mosaics adorning the upper walls and roof have perished, significant examples from the 9th century—following the Iconoclastic Controversy—have been uncovered. These include the Virgin with Child located in the apse, as well as a few remaining figures from a once-comprehensive series of saints that originally lined the nave walls.1