A celebrated piece of goldsmith's work of the tenth century is the Pala d'Oro at St. Mark's in Venice. This is a gold altar piece or reredos, about eleven feet long and seven feet high, richly wrought in the Byzantine style, and set with enamels and precious stones. The peculiar quality of the surface of the gold still lingers in the memory; it looks almost liquid, and suggests the appearance of metal in a fluid state. On its wonderful divisions and arched compartments are no less than twelve hundred pearls, and twelve hundred other precious gems. These stones surround the openings in which are placed the very beautiful enamel figures of saints and sacred personages. St. Michael occupies a prominent position; the figure is partly in relief. The largest medallion contains the figure of Christ in glory, and in other compartments may be seen even such secular personages as the Empress Irene, and the Doge who was ruling Venice at the time this altar piece was put in place--the year 1106. The Pala d'Oro is worked in the champleve process, the ground having been cut away to receive the melted enamel. It is undoubtedly a Byzantine work; the Doge Orseolo, in 976, ordered it to be made by the enamellers of Constantinople. It was not finished for nearly two centuries, arriving in Venice in 1102, when the portrait of the Doge then reigning was added to it. The Byzantine range of colours was copious; they had white, two reds, bright and dark, dark and light blue, green, violet, yellow, flesh tint, and black. These tints were always fused separately, one in each cloison: the Greeks in this period never tried to blend colours, and more than one tint never appears in a compartment. The enlarging and improving of the Pam d'Oro was carried on by Greek artists in Venice in 1105. It was twice altered after that, once in the fourteenth century for Dandolo, and thus the pure Byzantine type is somewhat invaded by the Gothic spirit. The restorations in 1345 were presided over by Gianmaria Boninsegna. One of the most noted specimens of enamel work is on the Crown of Charlemagne,[1] which is a magnificent structure of eight plaques of gold, joined by hinges, and surmounted by a cross in the front, and an arch crossing the whole like a rib from back to front. The other cross rib has been lost, but originally the crown was arched by two ribs at the top. The plates of gold are ornamented, one with jewels, and filigree, and the next with a large figure in enamel. These figures are similar to those occurring on the Pala d'Oro. [Footnote 1: See Fig. 1.] [Illustration: DETAIL; SHRINE OF THE THREE KINGS, COLOGNE] The Shrine of the Three Kings in Cologne is decorated both with cloisonne and champleve enamels,--an unusual circumstance. In Aix la Chapelle the shrine of Charlemagne is extremely like it in some respects, but the only enamels are in champleve. Good examples of translucent enamels in relief may be seen on several of the reliquaries at Aix la Chapelle.