The wide discrepancy of the dates, 888 to 1148, may perhaps be accounted for by the conjecture that the work of the building [the Campanile] proceeded slowly, either with a view to allowing the foundations to consolidate, or owing to lack of funds, and that the chroniclers recorded each resumption of work as the beginning of the work. One point may, perhaps, be fixt. The Campanile must have been some way above ground by the year 997, for the hospital founded by the sainted Doge, Pietro Orseolo, which is said to have been attached to the base of the tower, was consecrated in that year. The Campanile was finished, as far as the bell-chamber at least, in 1148, under the Doge Domenico Moresini, whose sarcophagus and bust surmount the portal of the San Nicoll del Lido.
The chroniclers are at variance among themselves as to the date of the foundation, nor has an examination of the foundations themselves led to any discovery which enables us to deter-mine that date; but one or two considerations would induce us to discard the earlier epochs. The foundations must have been designed to carry a tower of the same breadth, tho possibly not of the same height, as that which has recently fallen. But in the year of 888 had the Venetians such a conception of their greatness as to project a tower far more massive than any which had been hitherto constructed in Italy? Did they possess the wealth to justify them in such an enterprise? Would they have designed such a tower to match St. Mark’s, which was at that time a small church with walls of wood? It is more probable that the construction of the Campanile belongs to the period of the second church of St. Mark, which was begun after the fire of 976 and consecrated in 1094.
The height of the Campanile at the time of its fall was 98.60 meters (322 ft.), from the base to the head of the angel, tho a considerable portion of this height was not added till 1510; its width at the base of the shaft 12.80 meters (35 ft. 2 in.), and one meter (3 ft. 3 in.) less at the top of the shaft. The weight has been calculated at about 18,000 tons.
Thanks to. excavations at the base of the tower made by Coin. Giacomo Boni, at the request of Mr. C. H. Blackall, of Boston, U. S. A., in the year 1885, a report of which was printed in the Archivio Veneto, we possess some accurate knowledge about a portion of the foundation upon which this enormous mass rested.
The subsoil of Venice is composed of layers of clay, sometimes traversed by layers of peat, overlying profound strata of watery sand. This clay is, in places, of a remarkably firm consistency; for example, in the quarter of the town known as Dorsoduro or “hard-back,” and at the spot where the Campanile stood. A bore made at that point brought up a greenish, compact clay mixed with fine shells. This clay, when dried, offered the resisting power of half-baked brick. It is the remarkable firmness of this clay which enabled the Venetians to raise so ponderous a structure upon so narrow a foundation.
The builders of the Campanile proceeded as follows: Into this bed of compact clay they first drove piles of about 9½ in. in diameter with a view to consolidate still further, by pressure, the area selected. That area only extends 1.25 meter, or about 4 ft. beyond the spring of the brickwork shaft of the tower. How deep these piles reach Boni’s report does not state. The piles, ‘at the point where he laid the foundation bare, were found to be of white poplar, in remarkably sound condition, retaining their color, and presenting closely twisted fiber. The clay in which they were embedded has preserved them almost intact. The piles extended for one row only beyond the superimposed structure. On the top of these piles the builders laid a platform consisting of two layers of oak beams, crosswise. The lower layer runs in the line of the Piazza, east to west, the upper in the line of the Piazzetta, north to south. Each beam is square and a little over 4 in. thick. This oak platform appears to be in had condition; the timbers are blackened and friable. While the excavation was in progress seawater burst through the interstices, which had to be plugged.
Upon this platform was laid the foundation proper. This consisted of seven courses of stone of various sizes and of various kindssandstone of two qualities, limestone from Istria and Verona, probably taken from older buildings on the mainland, certainly not fresh-hewn from the quarry. The seventh or lowest course was the deepest, and was the only one which escaped, and that but slightly; the remaining six courses were intended to be perpendicular. These courses varied widely from each other in thicknessfrom 0.31 to 0.90 meters. They were composed of different and ill-assorted stone, and were held together in places by shallow-biting clamps of iron, and by a mortar of white Istrian lime, which, not being hydraulic, and having little affinity for sand, had become disintegrated. Boni calls attention to the careless structure of this foundation proper, and maintains that it was designed to carry a tower of about two-thirds of the actual height imposed upon it, but not more.
Above the foundation proper came the base. This consisted of five courses of stone set in stepwise. These courses of the base were all the same kind of stone, in fairly regular blocks, and of fairly uniform thickness. They were all in-tended to be seen, and originally rose from the old brick pavement of the Piazza; but the gradual subsidence of the soilwhich is calculated as proceeding at the rate of nearly a meter per 1,000 yearscaused two and a half of these stepped courses to disappear, and only two and a half emerged from the present pavement.
Thus the structure upon which the brick shaft of the Campanile rested was composed of (1) the base of five stepped courses, (2) the foundations of seven courses almost perpendicular, (3) the platform of oak beams, and (4) the piles. The height of the foundation, including the base, was 5.02 meters, about 16 ft., or one-twentieth of the height they carried. Not only is this a very small proportion, but it will be further observed that the tradition of star-shaped supports to the foundations is destroyed, and that they covered a very restricted area. In fact, the foundations of the Campanile belonged to the primitive or narrow kind. The foundations of the Ducal Palace, on the other hand, belonged to the more recent or extended kind. Those foundations do not rest on piles, but on a very broad platform of larch beamsmuch thicker than the oak beams of the Campanile platformreposing directly on the clay. Upon this platform, foundations with a distended escarpment were built to carry the walls, the weight of which was thus distributed equally over a wide area.
Little of the old foundations of the Campanile will remain when the work on the new foundations is completed. The primitive piles and platform are to stand; but new piles have been driven in all round the original nucleus, and on them are being laid large blocks of Istrian stone, which will be so deeply bonded into the old foundations that hardly more than a central core of the early work will be left.
In a peculiar fashion the Campanile of San Marco summed up the whole life of the city-civil, religious, commercial, and militaryand became the central point of Venetian sentiment. For the tower served the double needs of the ecclesiastic and the civic sides of the Republic. Its bells marked the canonical hours; rang the workman to his work, the merchant to his desk, the statesman to the Senate; they pealed for victory or tolled for the demise of a Doge. The tower, moreover, during the long course of its construction, roughly speaking, from the middle of the tenth to the opening of the sixteenth centuries, was contemporary with all that was greatest in Venetian history; for the close of the tenth century saw the conquest of Dalmatia, and the foundations of Venetian supremacy in the Adriaticthat water-avenue to the Levant and the Orientwhile by the opening of the sixteenth the Cape route had been discovered, the League of Cambray was in sight, and the end at hand.
The tower, too, was a landmark to those at sea, and when the mariner had the Campanile of San Nicolo on the Lido covering the Campanile of St. Marks, he knew he had the route home and could make the Lido port. The tower was the center of popular festivals, such as that of the Svolo on Giovedi grasso, when an acrobat descended by a rope from the summit of the Campanile to the feet of the Doge, who was a spectator from the loggia of the Ducal Palace.