Justinian I constructed at Ephesus a large basilica church, the Basilica of St John, above the supposed tomb of John the Apostle. The church was a domed cruciform basilica begun in 535/6; enormous and lavishly decorated, it was built in the same style as Justinian's Church of the Holy Apostles in Constantinople. The Justinianic basilica replaced an earlier, smaller structure which Egeria had planned to visit in the 4th century, and remains of a aqueduct branch built to supply the complex with water probably dates from Justinian's reign. The Ephesians' basilicas to St Mary and St John were both equipped with baptisteries with filling and draining pipes: both fonts were flush with the floor and unsuitable for infant baptism. As with most Justinianic baptisteries in the Balkans and Asia Minor, the baptistery at the Basilica of St John was on the northern side of the basilica's nave; the 734 m2 baptistery was separated from the basilica by a 3 m-wide corridor. According to the 6th century Syriac writer John of Ephesus, a Syriac Orthodox Christian, the heterodox Miaphysites held ordination services in the courtyard of the Basilica of St John under cover of night. Somewhat outside the ancient city on the hill of Selçuk, the Justinianic basilica became the centre of the city after the 7th century Arab–Byzantine wars.