Saint John passed from Ephesus during his missionary journeys and stayed there for three years, accompanying the Virgin Mary. He is said to have written his gospel in Ephesus and that he also died there. The Emperor Justinian erected a big Basilica to Saint John, above his tomb in the 6th century AD.
The Basilica of Saint John was cruciform and 130 m long. There was an atrium at the front side and the church consisted of six domes supported by massive piers which had been erected between the naves. Two storeys of columns had been built between the naves and the monograms of Justinian and his wife Theodora had been engraved on the lower row of the columns.
Recent excavations have brought to light a baptistery, a pool and a chapel with frescoes which depicts Christian saints.
A part of the foundations which had been made of brick and the marble wall of the Basilica have been reconstructed and it is said that if it was restored fully, then it would be the seventh largest cathedral all over the world.
The Basilica of Saint John is located 3,5 km away from the ancient site of Ephesus, on the slope of Ayasoluk Hill. It used to be one of the most sacred places during the medieval age attracting a lot of pilgrimage. However, it was ruined due to Arabic invasions and it was converted to a mosque in 1330. In 1402, it was destroyed entirely by the army of Tamerlane Mongol.