The merit of this plan is that it unites itself, with little obstructiveness, with the church on all sides of it, and opens out in its centre a space of double the width of the nave. It is also pleasing and elegant in its effect. But it is time that we returned to the Byzantine type, which you will remember that we left at Ravenna to follow out this digression. We now adjourn from Ravenna to Venice. The mercantile and perhaps political connections of the old Venetians were mainly _Oriental_. This probably accounts for their architecture, up to the twelfth century being _Byzantine_. [Illustration: Fig. 438.--Plan, Cathedral at Sienna. (_From Fergusson._)] The Church of St. Mark, or the Chapel of the Doge’s Palace, was founded in the ninth century, in honour and for the reception of the body of St. Mark, which had been procured from Alexandria, when the church in which it had been long deposited was destroyed by the Moslems. This church, however, perished in a popular tumult, late in the tenth century, whereupon the Venetians set about its reconstruction with a determination to render it one of the finest and most sumptuous in existence (Fig. 439). All the East, so far as accessible to their ships, was laid under contribution for columns and other architectural embellishments. The design is often spoken of as founded on that of St. Sophia. This was not the case. The Church of the Apostles at Constantinople would rather seem to have furnished its model.[64] It consists of a group of five square spaces, covered each by its pendentive dome. Its peculiarity lies in the breadth of the strips of wagon-vault which support and separate these domes, which is so great that the vast piers which sustain them are pierced in two storeys, and divide each other into four piers, with a vaulted space between them. Each dome is consequently the centre of a cruciform space, the wings of which have wagon-vaults. The only exception is the east end, where an apse is substituted for this space, and out of this apse spring three minor ones, as at St. Sophia. Each dome is about hemispherical above its pendentives, and is pierced with windows, as at St. Sophia. [Illustration: Fig. 439.--Plan, St. Mark’s, Venice.] The domes are now, and have been for many ages, covered over by lofty domical towers of timber, each surmounted by a sort of turret on its apex (Fig. 440). The wings which flanked each domed space, bounded as they were by the perforated piers, were so suggestive of side aisles that the builders, familiar, no doubt, with aisled churches, added arcades from pier to pier, both in the nave and transepts. These, however, are merely decorative, supporting no galleries, as is frequent in the East, and only serving as narrow communications, equivalent to triforium passages, between the upper chambers in the great piers. [Illustration: Fig. 440.--Cross Section, St. Mark’s, Venice.]