Clavus is a band of arabesque embroidery or rich stuff of purple or other brilliant colors, worn on ecclesiastical vestments. The laticlave of the colobium was usually a wide band, reaching from the neck to the feet. In the chasuble it was pall-shaped, and called the pectoral, dorsal, onophorion, auriclave, and orphrey. It also occurs reaching no lower than the chest, where it is covered with roundels of metal and edged with little balls.
We continually find in ancient Christian frescos and mosaics garments decorated with long stripes of purple, sometimes enriched with embroidery or an inwoven pattern, called by .this name. These generally run from the top to the bottom of the garment, and are broader or narrower according to the dignity of the wearer. Thus, the Lord is often distinguished by a broader-clavus than those of the apostles, as in a fine fresco in the cemetery of St. Agnes. Unimportant persons also wore clavi, but very narrow. In nearly all cases these clavi are two in number, and run from each shoulder to the lower border of the dress. Tertullian (De Pallio, c. 4) speaks of the care which was taken in the selection of shades of color.
There are a few examples of the single clavus, running down the centre of the breast, which, Rubeiius -believes was the ancient fashion of wearing it. These occur only in representations of the Three Children in the Fiery Furnace.
Clavi are common to both sexes; women may be seen represented with that ornament, for instance, in pictures of the Wise and Foolish Virgins; and female figures are sometimes found adorned with two clavi on each side Jerome (Epist. 22, ad Eustochium) alludes to the use of the clavus by Women, single as well as married. It is also common in early art to personages of the Old Testament and the New; it is given to Moses, for instance, and to the apostles, in nearly all representations of them, whether in fresco, in mosaic, or in glass. Angels also wear the clavus in early mosaics, in the Menologium of Basil, and in several ancient miniatures.
These purple stripes were worn on the penula as well as the tunic a fresco from an arcosolium in the cemetery of Priscilla furnishes three examples. They are found also in the pallium: a mosaic of St. Agatha Major at Ravenna, represents our Lord with clavi of gold on such a garment. The dalmatic and colobiim were similarly decorated the latter seems to have had only one broad band of purple descending from the upper part of the chest to the feet.
Priests, after the example of the senators of old Rome, are said to have worn the broad clavls, while deacons contented. themselves with ;the narrow one on their tunics or dalmatics. The clavus is thus to some extent a mark of rank. 'The shorter kind, ornamented with small disks or spangles, and terminating in small globes or bulla,, is said to be the kind of decoration which is sometimes called pairagaudis. See Rubenius, De Re estiaria 'et Prceecipue de Lato Clavo (Antwerp, 1665).