The main portal of the church has a complex structure: it consists of three great arches arranged in diminishing order, each one decorated with bas-reliefs on the front and intrados.
The most recent scholarship concludes that the group was designed at one and the same time and carried out in the relatively brief period of about ten years, in the 13th century. The formal and stylistic discrepancies are imputable to the fact that the portal was decorated by a number of craftsmen.
THE INNERMOST INTRADOS
The relief on the innermost intrados shows two crouching figures identifiable as Satan and Lust, a usual couple in Romanesque iconography, from whom a vine shoot intertwined with pomegranate departs and surrounds simple depictions: animals, combat, fables (the fox and the grapes) and Samson Fighting the Lion. The archivolt of the first internal arch also has motifs of animals fighting, flanked by hunting scenes. In some cases it is impossible to determine even the actions of the figures (children, men, women, a centaur) and consequently their meaning. Many of the figures are simply crushing, breaking and pulling up the foliage that surrounds them. The Devil, Lust and the beasts allude to the evil that dominates the world. The archivolt shows examples of vice set in the selva oscura (dark forest) – which meant life to mediaeval man – through the allegory of hunting and through the depiction of ignoble actions.
MONTHS – VIRTUES AND BEATITUDES
The reliefs on the next arch are allegories of the human and religious principles on which the Christian world is based: the intrados has allegories of the twelve months accompanied by the signs of the Zodiac, and on the archivolt there are seventeen personifications of Virtues and Beatitudes.
The combination of images of the months and the signs of the Zodiac is widespread in both East and West. The iconography of the individual depictions – the activities typical to each month of the year – have characteristics that are more Byzantine than western. The portrayals of March as an armed warrior and April as a shepherd with a lamb on his shoulders are typically Byzantine. Seen as a whole the St. Mark’s cycle is not identical with any other, nor can it be said to derive from any other.
The cycle of Virtues and Beatitudes on the front of the arch is the work of various hands, as are all the subsequent parts of the portal, in which it can always be seen that the reliefs on both lower parts were done by the master while the upper parts, farther from sight, are of poorer quality because they were done by his assistants. The model for the Virtue cycle is the mosaic in the central cupola, datable to the late 12th century, where a theme of western origin is translated into a vaguely Byzantine-like style, whereas here the mosaic source is retranslated into a western idiom.
The internal decoration of the third arch that frames the mosaic of the Last Judgement is the most Venetian part of the whole decorative plan of the faï¿½ade of St. Mark’s. In place of the artes liberales of the French cathedrals what we have here are portrayals of Venetian trades.
The representation of Trades is a main element in the figurative decoration of the faï¿½ade of St Mark’s.
The link between the Last Judgement and the reliefs of Trades that frame it remains rather vague, even if one interprets these realistic and not at all allegorising images as exempla of good conduct. More than anything else they are actually an expression of the civic pride and self-celebration of the Venetian populus. Here too there are suggestions drawn from the atrium mosaics.
Compared with the vigorous realism of the Trades cycle the decoration of the archivolt of the same arch shows a clear drop in tone, not from a formal but from a thematic viewpoint. It consists of one of the many series of Prophets in St. Mark’s (nine including the interior mosaics). Here however the figures are nearly suffocated by the voluminous foliage framing them. Furthermore the total disappearance of the inscriptions that certainly once appeared on their scrolls makes interpretation of the individual persons and prophecies impossible. One may however suppose that the latter bore reference to the Last Judgement.
The work in which the virtuoso talent of the ‘cathedral’ craftsmen of St. Mark’s reached its peak – the relief on the archivolt of the portal’s external arch – is also the work most damaged by atmospheric agents.
It is difficult to make out the hands at work. Nonetheless it is certain that here, over and above the Maestro of the Trades, the Maestro of Hercules or one of his best assistants was involved: the physiognomies have close affinities with the works of his circle.
The Arch of the Prophets is the latest and most mature west faï¿½ade sculpture and is purely Venetian art. One may at least presume with a degree of certainty that this grandiose work was created fairly late, approximately between 1250 and 1275, but at the same time very early in terms of the surprising modernity of, for example, the vine-shoots that wind into space. In these elements the evolution of Venetian ornamental art seems to prefigure the advent of flamboyant Gothic.