Known as the youngest apostle of Jesus, St. John (St. John the Theologian, the Gospel Writer, also known as John the Baptist) settled in Ephesos and was buried on Ayasuluk Hill at his request. St. John’s burial here led to the area becoming a vital worship center and the construction of various structures over time.
Thanks to excavations that began in 1921 and have continued intermittently to this day, three construction phases have been identified in the region. During the 300s CE, when Christianity was spreading and later became the official religion of Rome, a simple mausoleum was constructed over the burial site of St. John. During the second phase, corresponding to the 4th and 5th centuries CE, an early Christian basilica with a wooden roof was built, centering around this mausoleum. In the final phase, corresponding to the 6th century CE, a large cross-shaped and domed church was constructed by the Eastern Roman Emperor Justinian and his wife, Empress Theodora, replacing the basilica that had become unusable due to earthquakes. This church, the largest religious structure in Ephesos after the Temple of Artemis, is believed to have been designed by the architects Anthemios of Tralles (Aydın) and Isidoros, who also designed the Hagia Sophia Cathedral.
St. John Church holds a special place in early Byzantine architecture due to its size and cross-shaped and domed structure. The church included features such as a chapel, treasury room, baptistery, and courtyard to enhance its architectural grandeur. During the Middle Ages, St. John Church was a popular pilgrimage site for Christians and earned the title of “Pilgrimage Church.” It maintained its importance until the early 14th century. The traveler Ibn Battuta, who visited Selcuk during this period, mentioned St. John Church in his travelogue. However, the fact that later travelers do not mention the church confirms that an earthquake in the second half of the 14th century destroyed it.
Excavations in the area, initiated in 1921 by G. A. Sotiriou, continued between 1927 and 1931 under the leadership of H. Hormann and F. Miltner on behalf of the Austrian Archaeological Institute. In 1957, G. B. Quatmann, who visited St. John Church, reported the need for restoration to the authorities and advocated for its repair. Following this initiative, restoration work was carried out between 1960 and 1963 under the leadership of H. Gültekin and M. Baran. Excavations resumed in 1974 under the leadership of Prof. Dr. Ekrem Akurgal, with the support of the Quatmann family, and continued uninterrupted until 1998. Between 2007 and 2019, excavations and restoration work were conducted under the leadership of Dr. Mustafa Büyükkolancı, bringing St. John Church to its current state. Since 2020, work in the area has been carried out under the leadership of Assoc. Prof. Dr. Sinan Mimaroğlu.