The lintel of the bronze door-frame bears a relief. This represents an arch, supported by columns above a throne with the book of the Gospel and the descent of the Holy Ghost in the form of a dove. On it are the words of S. John, ‘The Lord said, I am the door of the sheep; through me if any man enter, he shall enter and shall go out, and shall find pasture.’ The simple bronze door-plating now remaining does not seem to be original. [See p. [265].]
Salzenberg,[273] as an example of the marble frames, gives the east door of north aisle. Like all Byzantine door-frames, the head does not cut across the jamb, but mitres. This perhaps made it easier for fixing within the openings left in the walls. Salzenberg[274] also represents the arched opening, which stands between the Baptistery and the small court on the south side of the church.[275] There are two tiers of columns, with a thin architrave band between them. The door stands between the lower columns; to avoid concealing them the frame is made as small as possible, as the plan shows. A similar arrangement is found in the earlier church of S. John Studius.[276]
The bronze door-plating on the exterior of the south porch entrance is extremely interesting.[277] A wooden foundation four or five inches thick is covered with ornamental bronze casings. The borders to the panels are beautifully modelled, and must be ancient. The other outer margins, with knobs and rosettes, and the four panels, which are decorated with monograms, belong to the Byzantine school. In the more ancient parts the metal is one-eighth to one-fourth inch in thickness, in the latter it is three-eighths to half an inch. Antique doors must have been enlarged and fitted with new panel plates.
Marble Plating.—Broad horizontal bands run round the nave at different heights, and the spaces between them are filled with single panels and vertical sheathing. All the bands and panels have notched fillets, 1½″ wide, of white marble as borders. The more important panels have sculptured white marble frames, eleven inches wide with a “pater noster” and notched-fillet borders on either side.
The spandrils of the upper arches and the bands beneath the topmost cornices are incrusted with designs of leaves, flowers, fruits, and birds formed of different kinds of marble.
The marble casing to the walls of the nave is arranged as follows.[278] Above the skirting is a [3′.10″] band of verde antique, then the notched fillet, then a [1′.5½″] yellow band [oriental alabaster]; above this is a vertical sheeting [7′.10″] formed of Pavonazzetto marble, alternating with a yellowish brown marble; then another horizontal band of yellow.
Above this stretches a series of panels round the whole nave—a panel of rosso, with two vertical slabs of a dark marble like porto venere on either side, each surrounded by the sculptured frames. The space from the top of this series to the lowest cornice is adorned with two bands of yellow [alabaster], and between them is sheathing similar to that below.
The upper division of the nave starts above the cornice with horizontal bands of white and verde antique; above which are vertical panels of porphyry, set in a frame of yellow [alabaster], with slabs of the russet marble on either side. [Then follows another horizontal band of oriental alabaster, and above it a range of vertical slabs of verde antique alternating with Synnadan.]
Beyond this again, and immediately below the upper cornice, is the band made up of different marbles[279] [opus sectile]. A dark brown marble forms the groundwork, the tendril ornament is white, and the rest is of red, like rosso antico, and of green serpentine. Similar work incrusts the spandrils of the gynaeceum arcade. The centre of each is a disc of green marble, and the whole spandril is edged by a three-inch strip of pale red. Above the centre of each arch in this spandril decoration are discs containing crosses, from the arms of which hang seals.[280] The soffites of the arches are covered with glass mosaic. The aisles are lined with marbles similarly arranged to those in the nave.
The walls of the bema are covered with panels of inlaid marble.[281] These panels in pairs are separated by a plain slab of porphyry. By the side of the arched opening into the gynaeceum is a panel of porphyry with a pattern in slight relief, and surrounded with yellow alabaster. The arched opening into the gynaeceum is closed with a parapet of white marble, with a carved framework above, formerly fitted, as holes show, with a metal lattice.