Which Byzantine palace in Istanbul was the principal imperial residence before the Topkapı Palace?

The Great Palace of Constantinople was the principal imperial residence before the Topkapı Palace.

Also called the Sacred Palace, the complex occupied a large area between Hagia Sophia and the Hippodrome. Construction began under Constantine the Great and continued for centuries as emperors expanded, rebuilt, and redecorated its halls, churches, courtyards, and ceremonial spaces.

The palace was not a single uniform building but an evolving imperial compound. The surviving Palace of Lausus, the Chrysotriklinos, the Magnaura, and the Boukoleon waterfront palace were among structures associated with the wider complex. The famous sixth-century mosaic pavement now displayed in Istanbul’s Great Palace Mosaic Museum came from this palace area.

After the Latin occupation and the later decline of Constantinople, emperors increasingly favored the Blachernae Palace. Following the Ottoman conquest, the Great Palace largely disappeared, while Topkapı became the new imperial center.