The remarkable universality of the fret, the simplicity and rhythm of detail, its adaptability and usefulness for surface enrichment, have made the fret one of the best known forms of ornamentation. It was used in the surface decorations of the tombs of Egypt, the temples of Greece, and the civic and domestic buildings of Rome.

The Greek form with its right-angular and equally-spaced keys was used on the simple abacus and plain fascias of the Dorian architecture, in bands upon the painted vases, and in a concentric form when used in the interior of the red-figured circular cylix. The Romans, without imparting freshness, used the same right-angled key pattern, chiefly as borders for mosaic pavements and upon the horizontal soffits of their architecture. The Byzantine using the same type in conjunction with the cross and circle gave more significance to the fret.

The Arabian fret differs in the use of the oblique line together with the right-angled key, obtaining a wonderful degree of complexity and richness.

The Celtic fret is chiefly a diagonal one, but the recurrent angle is rounded to a curve.

Chinese and Japanese frets are usually right-angled, and are used in great profusion, often in a secondary field or background.

The Japanese key or “Fret diaper” is used in the greatest profusion; it is used alike on silks and brocades, damascened in metal, in cloisonnÉ enamel and in lacquered work, and is frequently arranged in irregular shaped compartments or medallions.

The Greek continuous fret border is rarely used by the Japanese, who generally use the disconnected or irregular fret. A similar irregular fret border was used by the Peruvians (plate 41), by the Mexicans, and by the natives of Polynesia.

The Assyrian and Byzantine guilloche is but a curved fret, but additional interest is given by the introduction of radiating forms in the principal interstices of the fret (fig. 5, plate 11.)