Byzantine Churches in Constantinople Part 8

THE BAPTISTERY, S. SOPHIA. THE INTERIOR, LOOKING WEST.

_To face page 76._]

[Ill.u.s.tration: FIG. 21.--VIEW OF THE EXTERIOR OF THE DOME OF SS. SERGIUS AND BACCHUS.]

On the other hand the eight compartments directly above the angles of the octagon are narrower than the preceding compartments; they have no windows, and, what is of special importance to note, they are deeply concave.[115] Such marked hollowness is found in later domes as a decorative feature, but here it is primarily and supremely a constructive device. By its means the concave compartments are set slightly back from the octagon's inner face, leaving, at the springing line, portions of the wall-head to appear as little flat ledges on each side of the angles. This is a most skilful expedient, and compares favourably with the methods employed elsewhere to apply the dome to the octagon.[116] In the octagonal church of S. Lorenzo at Milan the octagon is turned into the circle by the introduction of squinches. In San Vitale a considerable walling is built between the line of the octagon and the springing line of the dome, while the bed for the dome is formed by introducing, in the s.p.a.ce over the angles of the octagon, niches which are worked above to the circle on plan. On the other hand, it is interesting to compare with these methods the method employed in the baptistery of S. Sophia, now a Sultan's Turbe, near the southern entrance to the inner narthex. Although the walls of the building describe a square on the exterior, they form an octagon on the interior with semicircular bays at the diagonals, as in SS. Sergius and Bacchus.

But in the application of the dome the true pendentive is used. The baptistery was erected shortly before S. Sophia, and in view of the erection of the great church.

The curvature of the dome of SS. Sergius and Bacchus has three zones, which have respectively a radius of m. 8, (drawn from the centre of the octagon), m. 3-1/4, and m. 9-1/2, (centre about m. 2, below the springing of the dome). The first extends to a point a little above the heads of the dome windows; the second about m. 2 higher; the third to the crown of the dome. The groins stop short a little below the dome's apex, where they are arched into one another, leaving a saucer-shaped crown now capped by a Turkish finial. The dome is covered with lead, and presents an undulating surface owing to the protuberance of its eight concave compartments.[117]

The system of weighting and b.u.t.tressing the dome displays great skill, and will be best understood by studying Mr. Henderson's geometrical and constructive sections of the systems (Figs. 28, 29).

[Ill.u.s.tration: FIG. 22.--BRICK STAMPS IN SS. SERGIUS AND BACCHUS.

(From rubbings by Mr. A. E. Henderson.) _At east end of south aisle._ _In the gallery._]

[Ill.u.s.tration: FIG. 23.]

[Ill.u.s.tration: FIG. 24.]

[Ill.u.s.tration: FIGS. 25, 26, AND 27.]

[Ill.u.s.tration: FIG. 28.]

[Ill.u.s.tration: FIG. 29.]

[Ill.u.s.tration: FIG. 30.]

[81] Procop. _De aed._ i. c. 4; Banduri, iii. p. 45.

[82] _De top._ ii. c. 14.

[83] Cedren. ii. pp. 642-43.

[84] Mansi, viii. col. 1010.

[85] Banduri, iii. p. 45. The church was visited by Russian pilgrims in 1200, 1350, 1393.--_Itin. russes_, pp. 160, 120, 164.

[86] Procop. _De aed._ i. p. 186. S. Peter 'near the palace' is mentioned in the list of abbots at the Synod of C.P. in 536. Mansi, viii. col. 930, col. 939. Another doc.u.ment of the same Synod, col.

1010, is signed by Peter, hegoumenos of SS. Peter and Paul and of the holy martyrs SS. Sergius and Bacchus.

[87] Diehl, _Manuel d'art byzantin_, p. 31. Antoniadi has drawn my attention to the junction of a basilica and a hexagonal building in a baptistery at Tivoli. See Dehio und Bezold, _Atlas_, plate i. fig. 10.

[88] Synax, Oct. 7.

[89] Du Cange, iv. p. 135.

[90] Cedren. i. p. 635; Procop. _Secret History_, c. 6; Procop. _De aed._ ii. p. 234; Theoph. p. 339; Theoph. Cont. p. 154.

[91] Cedren. i. pp. 642-43. The Synaxaria (Sirmondi) speak of three churches of S. Sergius, in or near Constantinople; [Greek: en tais Sophiais], Oct. 7; [Greek: plesion tes Aetiou kinsternes, Nov. 9 (near Monastery of Manuel, p. 258); [Greek: peran en Rhouphinianais], May 29 (near Kadikeui).]

[92] Page 220.

[93] Baronius, _Annales ecclesiastici_, tom. ix. p. 253, Luccae, 1741: 'quam basilicam eorum hic in domo nostra sub nomine praedictorum venerabilium constructam, ill.u.s.trare et illuminare large dignemini.'

[94] _Ibid._ p. 254.

[95] _De aed._ i. p. 186.

[96] _Ut supra_, [Greek: kai epeita kai temenos allo ek plagiou touto parakeimenon] (i.e. SS. Sergius and Bacchus).

[97] Baronius, x. p. 43.

[98] Theoph. p. 349; Malalas, p. 485.

[99] Le Grand Palais. Epigram 8 in the _Anthologia Graeca epigrammatum_ (vol. i. Stadt-Mueller) celebrates the erection by Justinian of SS. Peter and Paul, [Greek: eis ton naon ton hagion apostolon plesion tou hagiou Sergiou eis ta Hormisdou].

[100] Baronius, x. p. 43 'ex domo Placidiana, ubi degebat, confugit ad ibi proxime junctam ecclesiam S. Petri'; cf. Vigilius' letter, _Ep._ vii. t. i. _Ep. Rom. pont._

[101] Theoph. p. 349; Malalas, p. 485.

[102] _Not.i.tia_. Two palaces bearing similar names stood in the First Region of the city, the _Palatium Placidianum_ and the _Domus Placidiae Augustae_. Vigilius refers to the palace in his circular letter, giving an account of his treatment at Constantinople. There also the legates of Pope Agatho were lodged in 680, on the occasion of the First Council in Trullo, and there likewise Pope Constantine in 710, when he came to the East at the command of Justinian II., took up his abode.--Anastasius Bibliothecarius, pp. 54, 65.

[103] Epistola ccli. See Du Cange, _Const. Christ._ iv. p. 116.

[104] 'Under the microscope of modern historical criticism, ... it is not surprising to find that the famous emba.s.sy of John the Grammarian to the court of Baghdad must be rejected as a fiction irreconcilable with fact.'--Prof. Bury in the _English Historical Review_, April 1909. But he was sent on other emba.s.sies.

[105] Constant. Porphyr. pp. 87-88.

[106] Similar to the parakypticon at the east end of the southern gallery in S. Sophia. Reiske (_Comment. ad Constant. Porphyr._ p. 195) defines it as 'Fenestra, quae in sacrificatorium despicit e catechumeniis.' Cf. on the whole subject, Antoniadi, [Greek: Ekphrasis tes Hagias Sophias], vol. ii. p. 291, note 101; p. 331, note 190; p.

332.

[107] The plan of SS. Sergius and Bacchus is similar to that of the cathedral of Bosra (511-12), which was also dedicated to the same saints. Fergusson, _History of Ancient and Mediaeval Architecture_, vol. i. p. 432.

[108] Gyllius, _De Top. C.P._ ii. c. 16. If the design represented vine leaves and grapes, it surely did not allude to the G.o.d Bacchus, but to the vine in the gospel of S. John. The small columns on the piers are Turkish.

[109] Antoniadi, _S. Sophia_, vol. ii, pp. 7-9, draws attention to the development of buildings with sides turned into exhedrae, from their simplest form to their culmination in S. Sophia. He refers for ill.u.s.trations to plans in Dehio und Bezold, _Die kirchliche Baukunst des Abendlandes_, vol. i. pp. 23-31; _Atlas_, vol. i. plate i. figures 1, 2, 3, 4, 7; plate iii. figures 1, 2, 7.

[110] C. Diehl, _Theodora_, pp. 242, 342.

[111] The ratio of the height of the gallery above the floor of the church to the height of the summit of the dome is, according to Antoniadi, 1/3.5, the same as in S. Sophia as built by Anthemius.

[112] 'Pulvins,' says Rivoira (_Lombardic Architecture_, p. 11, English translation), 'serve the purpose of providing the springers of the arches with a base corresponding to the wall which they carry, while allowing the support beneath to be much slighter without injuring the stability of the structure.'

[113] Rivoira, _ut supra_, p. 62: 'The volutes in the Pseudo-Ionic capital intended to conceal the abruptness of the transition from the square of the pulvin to the round.'

[114] _De aed._ i. p. 187.

[115] 'The centres of the radii of these concave compartments are formed by having three points given the groins on either side and the angle of the octagon in the centre. With these points for each compartment the radius is given, and an arc turned giving the concavity required for each web at its springing.'--A. E. Henderson in the _Builder_, January 1906, p. 4.