Saint John died in Ephesus, and Emperor Justinian, in the first half of the 6th century, ordered a basilica to be built over his grave, which is now located on the Ayasuluk hills, east of the temple of Artemis.

An excerpt from the article 30 facts about Epheseus

During excavations around the tomb of St. John, five small tombs were discovered. Together with the tomb of St. John, they form the sign of the cross. Coins from the second half of the 1st century were also found there, which proves that this place was visited by pilgrims. Saint's John tomb was not plundered (the temple of Artemis was plundered many times).