St John is believed to have spent the last years of his life in Ephesus writing the Gospel of John. Emperor Justinian (527-565 AD) believed that a tomb dating from the 300s was John’s, so he built a great church above it in the 500s. After the death of Christ, St. John came with Mary to Ephesus, living most of his life in and around Ayasoluk Hill and spreading the word of Christianity as St. Paul did before him. It was here that he wrote the Gospel that bears his name. St. John’s grave was marked by a memorial and enclosed by a church of modest proportions in the 4th century. During the reign of Justinian, the emperor had a magnificent domed basilica constructed on the site.
The tomb of St. John, located under the main central dome, elevated the site to one of the most sacred destinations in the Middle Ages. With the decline in the importance of Ephesus and after repeated Arab raids, the basilica fell into ruins. The current entrance leads into the basilica through the southern transept. Originally, entry was through the oversize exterior courtyard atrium to the west of the nave, which led worshipers through the narthex and finally into the far end of the nave. The basilica had six domes. The brick foundations and marble walls have been partially reconstructed; if they were fully restored, the cathedral would be the seventh-largest in the world. More recent excavations east of the apse have revealed a baptistery and central pool, along with an attached chapel covered in frescoes depicting the saints.