The earliest enamels of incontestably Byzantine origin, which can be dated with accuracy by documentary evidence, seem to go no further back than the beginning of the tenth century. It cannot, however, be said that these works, with those of closely subsequent periods, have the appearance of being the productions of the school in its infancy and early development. Very considerable technical accomplishment is shown in the manipulation of the extremely narrow gold cloisons, disposed for the most part in straight or slightly curved lines, and filling even the spaces of the drapery with closely laid chevrons or parallel stripes; while the innumerable minute cells thus formed are filled with homogeneous, brilliant, many-hued enamels. A warm tone of pink is invariably used to represent flesh. An impressive object, possessing certain characteristics in common with the Jewel and other supposed Celtic-Saxon enamels, is the eagle fibula found at Mainz, and now in the museum there. The present setting of the enamelled eagle has been supposed to be Frankish, of the latter part of the tenth or earlier years of the eleventh century, and the eight small enamelled jewels inserted in the border confirm this view, as they closely resemble the jewels incrusted upon the frame of the Crucifixion plaque in the Reiche-Capelle at Munich, which has usually been attributed to that age (Von Hefner-Alteneck, _Trachten des christlichen Mittelalters_; Schlumberger, _Nicephorus Phocas_). The figure of the eagle, presumably, consisted originally of five plaques, one representing the head, another the tail, two others the outspread wings, and a fifth the body of the bird. This last is missing, its place having been supplied, apparently at the time the setting was made, by a plaque of engraved gold. This circumstance seems in favour of the idea that the enamels are of foreign workmanship, and earlier than the setting. The cloisons of neither the eagle nor the Roach Smith ouche are as narrow as those employed by the Byzantine enamellers, although they are at most only half the width of those made use of in the Alfred Jewel. The doubling of the cloisons into loops, not commonly seen in Byzantine work but remarkable in the Jewel, is also noticeable in the eagle. Amongst the five colours employed in the eagle are the dark, translucent green, and the yellow, considered by Mr. Gardner as characteristic of Celtic-Saxon enamels, and also the opaque white such as is used for the flesh tint in the Jewel and the ouche, and, as Labarte particularly remarks, in the closely analogous heads upon the altar of Saint Ambrose.