The Byzantines perfected a unique form of "cloisonné" icons. Byzantine enamel spread to surrounding cultures and a particular type, often known as garnet cloisonné is widely found in the Migration Period art of the "barbarian" peoples of Europe, who used gemstones, especially red garnets, as well as glass and enamel, with small thick-walled cloisons. Red garnets and gold made an attractive contrast of colours, and for Christians the garnet was a symbol of Christ. This type is now thought to have originated in the Late Antique Eastern Roman Empire and to have initially reached the Migration peoples as diplomatic gifts of objects probably made in Constantinople, then copied by their own goldsmiths. Glass-paste "cloisonné" was made in the same periods with similar results – compare the gold Anglo-Saxon fitting with garnets (right) and the Visigothic brooch with glass-paste in the gallery. Thick ribbons of gold were soldered to the base of the sunken area to be decorated to make the compartments, before adding the stones or paste. In the Byzantine world the technique was developed into the thin-wire style suitable only for enamel described below, which was imitated in Europe from about the Carolingian period onwards.