In Ancient Roman regalia

Regalia

Regalia is Latin plurale tantum for the privileges and the insignia characteristic of a Sovereign.The word stems from the Latin substantivation of the adjective regalis, 'regal', itself from Rex, 'king'...

, a laticlave, or clavus, was a broad stripe or band of purple on the fore part of the tunic

Tunic

A tunic is any of several types of clothing for the body, of various lengths reaching from the shoulders to somewhere between the hips and the ankles...

, worn by senator

Roman Senate

The Senate of the Roman Republic was a political institution in the ancient Roman Republic, however, it was not an elected body, but one whose members were appointed by the consuls, and later by the censors. After a magistrate served his term in office, it usually was followed with automatic...

s as an emblem of office, from which the difference of the tunica angusticlavia

Angusticlavia

An angusticlavia, or angusticlavus, in ancient Rome, was a narrow purple strip as garment worn on Roman tunica, or tunic. The angusticlavia was worn by the eques, or knight....

, and laticlavia.

This ornament, according to some, was called clavus, "nail", as being set with little round plates of gold, or silver, like the heads of nails.

Cantelius maintained that the clavus consisted of a kind of purple flowers, sewn upon the cloth.