The churches of Constantinople in the Justinian period
  Constantinople had several important churches, such as the Holy Apostles ( ), St Sophia , Sts Sergius and Bacchus, St Mary of Blachernai, St Mary at Chalkoprateia and St John Stoudios . The first year of Justinian's reign saw the completion of the magnificent church of St Polyeuktos (524-527) . Commissioned by the immensely rich Anicia Juliana, of the Roman patrician family of the Anicii, it was a very large church (about fifty metres square), lavishly decorated with floor and wall mosaics, a variety of colored marbles, columns inlaid with glass and amethysts, and elements of Proconnesian marble carved in a bewildering variety of motifs: peacocks with outspread tails, palm trees, orientalizing palmettes, curious vegetable forms, basket- and metalwork patterns. The opulent edifice displayed a conscious break with classical tradition and summarized the most recent trends in church building and decoration. The superstructure has not survived, but its powerful foundation walls argue for a domed ceiling. The church was divided into a nave and two aisles by a row of piers and columns. The side walls must have accomodated the six peacock niches, three on each side. The ambo was located in the centre of the nave. In the basement, a vaulted passageway led from the narthex to a crypt, situated under the sanctuary.
  Built by Justinian and Theodora in the Palace of Hormisdas, the church of Sts Sergius and Bacchus was probably destined for a colony of Syrian Monophysite monks. Roughly contemporary to St Sophia (it is first attested in 536), it was joined to a basilica dedicated to Sts Peter and Paul, both churches sharing the same atrium. The Palace of Hormisdas had been Justinian's residence during the reign of his uncle, Justin I (518-527), and was later connected with the Great Palace (527) next to which it stood. It was transformed into a monastery in 536, and was to be the home (from 542) of John of Ephesus, patriarch of Constantinople and author of many eastern saints' vitae, as well as of many persecuted citizens. The building has an octagonal nave inscribed within an irregular rectangle, and is covered by a dome (diam. 17 m) with alternately flat and concave segments. Columns of verde antico marble support a carved horizontal entablature, along the entire length of which runs an epigram in honor of Justinian and Theodora. A gallery repeats the arrangement of the ground level ambulatory.
  Before the inauguration of the old St Sophia in 360, St Irene was the cathedral of Constantinople. According to local tradition, the church pre-dated Constantine I, who enlarged it and gave it its current name. By the fifth century, St Irene and St Sophia were part of the complex of the patriarchate and served by the same clergy. They also shared the same fate. St Irene was destroyed during the Nika revolt and rebuilt by Justinian as a domed basilica, with two aisles on either side of the nave, and galleries over the aisles and narthex. A vaulted passage (kyklion) was constructed under the synthronon and used during the processions of the clergy required by the liturgy. The church suffered again from the earthquake of 740, after which the lateral arches supporting the dome were extended into deep barrel vaults reaching the exterior of the building.