When Constantine I (The emperor) moved the Roman capital to Constantinople in 330, he planned out a palace for himself and his heirs. The palace was located between the Hippodrome and Hagia Sophia. It was rebuilt and expanded several times, especially under the emperors Justinian I and Theophilos reign.
Until the early 13th century, the Great Palace served as the primary administrative and ceremonial centre of the city, although from the early Comnenian era the palace of Blachernae was favoured as an imperial residence. During the sack of Constantinople by the Fourth Crusade, the Palace was plundered by the soldiers of Boniface of Montferrat. Although the subsequent Latin emperors continued to use the Palace complex, they lacked money for its maintenance. The last Latin emperor, Baldwin II, went as far as removing the lead roofs of the Palace and selling them.
Consequently, when the city was retaken by the forces of Michael VIII Palaeologus in 1261, the Great Palace was in a bad state. The Palaeologus emperors largely abandoned it, ruling from Blachernae, so that when Mehmed II entered the city in 1453, he discovered it to be ruined and abandoned.
The Palace was located in the southeastern corner of the peninsula where Constantinople is situated, behind the Hippodrome and the Hagia Sophia. The Palace is considered by scholars to have been a series of pavilions, much like the Ottoman-era Topkapı Palace that succeeded it. The total surface area of the Great Palace exceeded 200,000 square feet (19,000 m2).
The main entrance to the Palace quarter was the Chalke gate at the Augustaion. The Augustaion was located on the south side of the Hagia Sophia, and it was there that the city's main street, the Mese ("Middle Street"), began. To the east of the square lay the Senate house or Palace of Magnaura, where the University was later housed, and to the west the Milion (the mile marker, from which all distances were measured), and the old Baths of Zeuxippus.
Immediately behind the Chalke Gate, facing southwards, were the barracks of the Palace Guards, the Scholae. After the barracks stood the reception hall of the 19 Accubita ("Nineteen Couches"), followed by the Palace of Daphne, in early Byzantine times the main imperial residence. It included the Octagon, the emperor's bedchamber. From the Daphne, a passage led directly to the imperial box (kathisma) in the Hippodrome. The main throne room was the Chrysotriklinos, built by Justin II, and expanded and renovated by Basil I. To its north lay the Triconchos palace, built by the emperor Theophilos and accessible through a semicircular antechamber known as the Sigma. To the east of the Triconchos lay the lavishly decorated Nea Ekklesia ("New Church"), built by Basil I, with five gilded domes. The church survived until after the Ottoman conquest. It was used as a gunpowder magazine and exploded when it was struck by lightning in 1490. Between the church and the sea walls lay the polo field of the Tzykanisterion.
Further to the south, detached from the main complex lays the seaside palace of Bucoleon. It was built by Theophilos, incorporating parts of the sea walls, and used extensively until the 13th century, especially during the Latin Empire (1204-1261) whose Catholic emperors from Western Europe favoured the seaside palace. A seaward gate gave direct access to the imperial harbour of Bucoleon.