The blue background of the plastered frieze just mentioned may remind us of the decoration of the beam above the columns of the ambo with gold ivy leaves on a background coloured ultramarine as described by the poet. (The spade-like leaves which occur in several places in the mosaic must be ivy.) This decoration of gold and “sapphire” seems to have been general in Byzantine work. The sculptured beam of the iconostasis at St. Luke’s has the blue background nearly intact, and here and there the gold is visible (Diehl, p. 26). Traces of the blue ground may also be noticed in the sculptures of Mone tes Choras at Constantinople. The notched fillet, which separates the marble panels in S. Sophia, is used so extensively at Venice that Mr. Ruskin called it the Venetian dentil; the complete intention of this fillet, he writes, is now only to be seen in pictures, “for like most of the rest of the mouldings of Venetian buildings it was always either gilded or painted--often both, gold being laid on the faces of the dentils and the recesses coloured alternately red and blue.”[412] It is clear from Paulus that at S. Sophia the sculptured capitals were all gilt (Part II., lines 129 and 244), as apparently were also the carved surfaces filling the spandrils of the lower arcade (line 236). The red colouring which Salzenberg notices was probably the preparation for the gold. It is thus almost certain that the notched fillets and carved frames of white marble surrounding the marble wall panels were gilt, as the Anonymous says, and coloured, thus reflecting as it were from the wall surfaces the brighter hues of the mosaic vaults. § 4. MONOGRAMS AND INSCRIPTIONS. The poet Paulus speaks of the iconostasis as bearing the names of the emperor and empress, combined in a monogram--“one letter that means many words.”