The monumental basilica was in the shape of a cross and was covered with six domes. Its construction, being of stone and brick, is an extremely rare find amongst the architecture of its time. Raised by two steps and covered with marble, the tomb of St John was under the central dome, that was once carried by the four columns at the corners. The columns in the courtyard reveals the monograms of Emperor Justinian and his wife Theodora. Constructed in the 5^th century AD, the baptistery is north of the nave, with its key hole shape. Rampart walls around the church were constructed for protection from the Arabian attracts in the 7^th - 8^th centuries AD. The impressive 10^th century AD frescoes representing St John, Jesus and a Saint, ornament the chapel. With the invasion of Turks, the chapel was used as a mosque in the 14^th century; unfortunately Basilica of Saint John  became unusable due to the serious earthquake in the same century.