CLAVI. - Trimming of the Roman tunic, the clavi were two parallel purple stripes which, passing over the shoulders, descended in front and behind to the lower hem. Their width varied according to circumstances, since, at least in early times, it was regulated by strict prescriptions.
Very narrow on the tunics of youths, the clavi worn by adults were distinguished into clavus (αἰτς ὕσλανόσηκος), the privilege of the emperor and the senatorial order, and clavus augustus (στενόσηκος), reserved for the equestrian order. As numerous paintings show, in which the clavus indiscriminately adorns the tunic of persons of every kind, this distinction of rank had, from the 1st century A.D. onward, lost much of its original strictness, unless such freedom is to be attributed to the artists, inclined to use it as an ornamental motif.
The double designation was also used to indicate both the tunic itself and the person who wore II.
From the 4th century onward, especially in Coptic tunics, the clavi are found ornamented and interrupted in such a way that they remain only at the top and bottom of the tunic.