Before we quit the interior, the old rich mosaic pavement with its quaint and beautiful Byzantine designs is worth notice. The uneven, wavy form is due, not to any intent of imitating the waves of the sea, but to the fact that the pavement is supported by the crypt and has settled into hollows corresponding to the cells of the vaulting which, being filled with loose material, are less rigid than the crown where no settlement has taken place. SECTION III _The Ducal Palace_ To turn from the fair temple of the Christian faith in Venice, warm with the affection and the presence of her people, to the empty splendour of the Palace where her secular princes sat in state, is to turn from life to death. If a patrician of the great days were to revive and enter St Mark’s he would find the same hierarchy, the same ritual, the same prayers and praise uttered in the same language to the God he knew. But if he sought to enter the Ducal Palace, the servant of a then petty dynasty would demand a silver coin before he were permitted to ascend the Golden Staircase. There, on steps once trod by those alone whose names were inscribed in the Book of Gold, he would meet a strange company. He would find the great palace of Venice a museum; her millennial power a memory; and the gorgeous halls that once echoed to the voices of the masters of land and sea occupied by a crowd of sightseers, alien in race and creed, gazing curiously at the faded emblems and pictures which tell of her pride, her glory and her imperial state. The earliest official residence of the Tribunes of Rivoalto was situated by the church of the Holy Apostles near the Rio dei Gesuiti, whose northern mouth is opposite the channel leading to Murano. The remains of this fortified building, which was furnished with a great gate, always kept closed, and a guarded postern, still existed towards the end of the sixteenth century, and then served as a prison. In 820, Doge Angelo Participazio built another feudal-like structure on the site of the present Ducal Palace, near the church of St Theodore. Nothing could be less like the _palazzo fabbricato in aria_ we know to-day. It and the whole of the Piazza, then but a third of its present area, were enclosed by a strong wall with Ghibelline battlements. One of the old towers is incorporated in the masonry, at whose corner now stand the four figures in porphyry referred to on p. 229.