(1) Since the moat necessarily follows the trend of the ground as it rises on either side from the beach to the dorsum of the peninsula, this canal, instead of maintaining a uniform level, consists of a number of sections divided by cross-walls, the distances between which are determined by the exigences of ascent or descent. In its course it outlines the contour of the walls, which advance on the peninsula from each end in the form of a bow. The average width of this foss is about sixty, and its depth about thirty feet. It is lined on both sides from the bottom with substantial stone walls, but, whilst that on the outside only reaches the level of the ground, the wall next the city, with a crenellated top, rises for several feet,[93] so as to convey the impression of a triple wall of defence. In peace time the water is allowed to run low, but if an assault is apprehended the trench can be quickly flooded by means of earthenware pipes concealed within the partition walls. From these conduits the city also derives a secret supply of water not likely to be tampered with by a besieging army.[94]
(2) At a distance of about twenty yards from the inner edge of the moat, rising to a height of nearly thirty feet, with dentated parapets, stands the lesser wall. Towers of various shapes, square, round, and octagonal, project from its external face at intervals of about fifty yards. Each tower overtops the wall and possesses small front and lateral windows, which overlook the level tract[95] stretching from the foss. High up in each tower is a floorway having an exit on the intramural space behind, and they have also steps outside which lead to the roof. The vacant interval between the walls is about fifty feet wide, usually called the peribolos.[96] It has been artificially raised to within a few feet of the top of the wall by pouring into it the earth recovered in excavating the moat.[97] This is the special vantage-ground of the defenders of the city during a siege: from hence mainly they launch their missiles against the enemy or engage them in a hand-to-hand fight should they succeed in crossing the moat and planting their scaling-ladders against the wall.[98]
(3) Bounding the peribolos posteriorly lies the main land-wall of Constantinople, the great and indisputable work of Theodosius II. In architectural configuration it is almost similar to the outer wall, but its height is much greater, and its towers, placed so as to alternate with the smaller ones in front, occupy more than four times as much ground. Built as separate structures, but adherent to the wall behind, they rise above it and project forwards into the interspace for more than half its breadth. Most of the towers are square, but those of circular or octagonal shape are not infrequent. In level places offering facilities for attack the wall has a general height of seventy feet, but in less accessible situations, on rising or rugged ground, it attains to little more than half that elevation.[99] As in the case of the outer defences, the wall and towers are crested by an uninterrupted series of crenellated battlements.
The towers are entered from the city at the back, and within each one is a winding stone staircase leading to the top. Here, sheltered by the parapet, there is room for sixty or seventy men to assail an enemy with darts or engines of war. There is also a lower floor from which a further body of soldiers can act on the offensive by means of front and side windows or loopholes. At intervals certain of the towers have an exit on the peribolos for the use of those militants who have their station on that rampart. In time of peace these towers serve as guard-houses, and the sentries are enjoined to maintain their vigilance by passing the word of each successive hour from post to post during the night.[100] The usual thickness of this wall is about eight feet, but no regular rampart has been prepared along the summit, the defensive value of such an area being superseded by the peribolos. Hence the top, the width of which is limited to less than five feet by the encroachment of the parapet, has no systematic means of access from the ground or from the towers. Hewn stone, worked in the vicinity, has been used for the construction of these fortifications,[101] and in some places close to the city the ground may be seen to have been quarried into hills and hollows[102] for the supply of the builders.[103]
At about every half mile of their length these walls are pierced by main gateways for the passing to and fro of the inhabitants. In these situations the inner wall is increased to more than treble its ordinary thickness, and the passage is flanked by a pair of the greater towers, which here approximate at much less than their usual distance. The thoroughfare consists of a deep and lofty archway, which on occasion can be closed by ponderous doors revolving on huge iron hinges. Opposite each gate the moat is crossed by wooden drawbridges easily removable in case of a siege. The most southerly entrance, being opposite the holy well, is called the Gate of the Fountain; next comes the Gate of Rhegium, then that of St. Romanus, fourthly the Charsios or oblique Gate,[104] and lastly the Xylokerkos Gate—that of the wooden circus. Between the third and fourth gates the moat is deficient and the walls are tunnelled for the transit of the streamlet Lycus, which, though almost dry in summer, swells to a considerable volume in winter. The second and last portals bear metrical inscriptions, differing verbally, but each declaring the fact that the Prefect, Cyrus Constantine, built the wall in two months.[105] On the second gate, that of Rhegium, the circumstance is recorded in a Latin tristich as well as in a Greek distich.[106]
Besides these popular approaches there is another series of five gates, architecturally similar, but designed only for military or strategic purposes. About intermediate in position and in line with neither roads nor bridges, they are closed to the general public and named merely in numerical succession from south to north.[107] Just above the third gate, that is, about half way between the Golden Horn and the Propontis, the walls dip inwards for a distance of nearly one hundred yards, forming a crescent or, as the Greeks call it, Sigma.[108]
The first strategic gate, first also of the land-wall, being scarcely a furlong from the Propontis, offers a notable exception to the constructive plainness of all the other entries. Intended only as a state entry to the capital for the display of Imperial pomp, it has been built and adorned with the object of rendering it the most splendid object in this part of the city. A pair of massive towers, each one hundred feet high, advance from a façade of equal altitude, which is traversed by three arched portals, that in the centre being elevated to sixty feet. The whole is constructed in white marble, and this chaste and imposing foundation is made resplendent by the addition of gilded statues, bas-reliefs, and mouldings. From a central pedestal above rises a figure of Victory[109] with flowing draperies, her hand extended offering a laurel crown. At her feet stands an equestrian statue of Theodosius the Great,[110] and from the extremity of each tower springs the two-headed Byzantine eagle.[111] Below, the surfaces of the monument are ensculptured all round with mythological designs,[112] among which we may recognize Prometheus the Fire-giver, Pegasus, Endymion, the labours of Hercules and many others. Corinthian columns of green-veined marble[113] bound the main portal, within which is erected a great cross.[114] In the fore area are placed a pair of marble elephants, recalling those used by Theodosius in his triumphal procession after the defeat of Maximus of Gaul; and behind these his grandson,[115] the builder of the gate, has raised a column bearing a statue of himself. Profusely gilded, this elaborate pile is popularly and officially known as the Golden Gate.[116]
To proceed with our survey we may re-embark on the Propontis and skirt the promontory by water from end to end of the land-wall, passing through the mouth of the Bosphorus between Europe and Asia and finishing our circuit in the upper reaches of the Golden Horn. The single south wall, rising from the brink of the sea, is similar to that of Anthemius, and the towers exhibit the same diversity of form.[117] Courses of rough stones immersed in the water lie along its base and form a kind of primitive breakwater, which saves its foundations from being sapped by the waves in tempestuous weather. These are said to have been quarried from the tops of the hills during the process of levelling the ground for the extension of the city, and then, at the suggestion of Constantine, sent rolling down the slopes until they became lodged in their present position.[118]
Several gates in this wall give access to the water, but they possess no architectural distinction. Westerly is the Porta Psamathia or Sand-gate, so called because an area of new ground has been formed here by silting up of sand outside the wall.[119] Near the opposite extremity is the Porta Ferrea or Iron-gate, thus designated from the unstable beach having been guarded by rails of iron to enable it to sustain the ponderous burdens imported by Constantine.[120] Towards the centre of this shore is situated the Gate of St. Aemilian, named from its proximity to a church sacred to that martyr.[121] More noticeable in this range of wall are the entrances to two excavated harbours, each closed by a chain stretching between a pair of containing towers. The first, at the foot of the Xerolophos, dates from the time of Constantine, who called it the Port of Eleutherius[122] after his master of the works. Remade by Theodosius I, it has since been most commonly associated with the name of that emperor.[123] Paved at the bottom and surrounded by a stone quay,[124] it is about a Roman mile in circuit,[125] and is divided centrally by a dike into an inner and outer basin.[126] More easterly is another similar but smaller harbour, having only one basin, designated Port Julian[127] from its Imperial founder, but it is more often spoken of as the New Port.[128] Owing, however, to the exceptional suitability for shipping of the north side of the city, both these harbours have gradually fallen into disuse and, becoming choked with sand, have been looked on merely as fit receptacles for the rubble accumulated in clearing building sites.[129] But the Port of Julian is soon to be reopened, for, at the direction of Anastasius, rotatory pumps have been fixed to empty it of its water and dredging operations are in progress.[130] To insure its continued patency a mole is even in course of construction in the Propontis over against its mouth.[131] Passing the Porta Ferrea, as we begin to round the headland, a large mansion or palace comes into view, substituted apparently for the wall in about fifty feet of its length. Fronted along its base with slabs of white marble, the edifice presents a lofty stone balcony overhanging the water,[132] and opening on to it, a central group of three rectangular windows or doors with jambs and lintels of sculptured stone. Above, a row of seven nearly semicircular windows indicates the uppermost floor of the building, which is known as the palace of the Boukoleon. Contiguous, to the west, we observe a small but very ornate harbour, formed on quite a different plan from those previously seen. Curved piers of masonry, enriched with marbles, extending from the land, inclose about an acre of water, which is approached from the city by flights of white marble steps.[133] On the intervening quay rests a handsome group of statuary representing a lion and a bull in the agonies of a death struggle.[134] This is the exclusive port of the Imperial Palace,[135] an important segment of which adjoins the wall at this point. Both palace and harbour have taken the name of Boukoleon from the piece of sculpture which so conspicuously marks the site.[136] In this vicinity, behind the wall on the city level, is the palace of the once famous Persian refugee, Prince Hormisdas.[137]
Farther on is a small entry from the water leading to a chapel sacred to the Theotokos, surnamed the Conductress, another foundation of the devout Pulcheria.[138] Here are preserved a portrait of the Virgin painted by St. Luke, the swaddling-clothes of Jesus, and other recondite memorials of Gospel history[139] grafted by imposture on the credulity of the age. This Conductress,[140] by virtue of a holy fount, is credited with being able to point out the way for the blind to receive their sight;[141] and a retreat for the blind, therefore, has been established on the spot.[142]