Basilica of St. John in Ephesus
The Basilica of St. John had its beginnings in the tetrapylon martyrion erected over the traditional location of St. John's tomb as early as around 300. Probably around 450 a cruciform church with a wooden roof was built on the site, incorporating the tetrapylon at its crossing. The western arm, with one or two narthexes, contained a nave and two aisles, while the eastern arm had four aisles and terminated in an apse. The church was rebuilt under Justinian I, with work beginning before 548 and completed prior to 565. The cruciform plan was maintained but the building was now covered with a series of six domes resting on massive piers. The western arm, longer than the others, consisted of two such bays, while the crossing, north, south, and east arms each had a single bay in a design described by Prokopios as closely resembling that of the Church of the Holy Apostles in Constantinople, which was also imitated later for the Basilica of San Marco in Venice. The nave and the transept were housed with six domes, so that the shape of the cross was evident. The church was flanked by an octagonal baptistery built in the 5th century and a domed, octagonal skeuophylakion (or sacristy) erected in the late 6th or early 7th century.
“There chanced to be a certain place before the city of Ephesus, lying on a steep slope hilly and bare of soil and incapable of producing crops, even should one attempt to cultivate them, but altogether hard and rough. On that site the natives had set up a church in early times to the Apostle John; this Apostle has been named ‘the Theologian,’ because the nature of God was described by him in a manner beyond the unaided power of man. This church, which was small and in a ruined condition because of its great age, the Emperor Justinian tore down to the ground and replaced by a church so large and beautiful, that, to speak briefly, it resembles very closely in all respects, and is a rival to, the shrine which he dedicated to all the Apostles in the imperial city, which I have described above.”
From Procopius' Buildings
The monograms of Justinian and emperor (basileos) of St. John at Ephesus are box monograms. The monograms of Justinian (IOYCTINIANOY) are based on the letter N, with the letter I contained in its upright. Both the letters T and a square C (Sigma) are to the right, with the letter A inserted within the left side of the N (in more than one variation), and the OY diphthong crowning the monogram. The monograms of Theodora (ΘEOΔѠPAC) of St. John at Ephesus are of the cruciform type, with the letters Θ (Theta), E, Ѡ (Omega), and A being attached to the cross. The O is incorporated in the Θ (Theta), while in some cases the Δ (Delta) is formed by added a bar beneath the A. The box monograms of ΒΑCΙΛΕѠΣ (basileos) based on the letters B and E with the letter Ѡ (Omega) above.
From the Nicholas V. Artamonoff Collection
Brickstamps of Constantinople by Jonathan Bardill