The fabric dates from the early eleventh to the late fourteenth centuries. Its core is of brick, of which most Venetian churches are built, and it is veneered with marble[85] and decorated with mosaic and sculpture. When the eye turns from the whole to examine details, the façade is seen to be composed of two tiers of arches--the lower of seven, the upper of five spans. Of the seven, two form the N. and S. porticos; five the western doors, whose recesses are enriched with rows of columns wanting in unity of design, but of exceeding richness and variety of material. They are mainly the spoils of Eastern churches, and, if closely scrutinised, will be found to be incised with Eastern crosses and curious inscriptions in Greek and oriental characters. The capitals flanking the main portal, with carving of leaves blown by the wind, are probably from the East, their prototype being at the Church of St Sophia in Thessalonica, built in the later years of Justinian’s reign. The main portal is spanned by an inner triple archivolt and an outer main one. The under side of the inner arc of the former, over the relief of St Mark and the Angel, is wrought with sculptures, whose subjects are symbolical, and will be met with again and again in early Venetian decoration: a naked man and woman seated on dragons; a child in the open jaws of a lion; an eagle pecking at a lamb; a lion devouring a stag; camels and other animals, wild and tame, in various groups. On the outer face are similar carvings of boys fighting and robbing birds’ nests; men shooting birds with bows and arrows, and hunting wild beasts. The work is exceedingly quaint, and affords a fruitful theme for interpretation. [Illustration: S. MARCO--DETAIL OF ARCHIVOLT] The sculptures on the under side of the outer arc symbolise the months of the year, with their appropriate celestial signs. May, a seated figure holding a rose and crowned with flowers by two maidens, is most beautiful and original in treatment. On the outer face of the archivolt are represented the Beatitudes and the Virtues, eight on either side of the keystone, which symbolises Constancy.