Whenever a male Roman citizen appeared in public, custom dictated that he wear his toga. This one piece of clothing was so important that by itself it visually proclaimed the distinction between slave and free, as well as between Roman and foreign. Their more conservative peers frowned upon Roman men who declined to dress according to their station. In his work concerning the decline of oratory, Cornelius Tacitus makes a derogatory reference to Romans appearing in public wearing only their tunies:

Again, is there an accomplishment, the fame and glory of which are to be compared with the distinction of an orator? Whom, as he passes by, do the ignorant mob and the men with the tunic oftener speak of by name and point out with the finger?

Source: Cornelius Tacitus, Dialogue on Orators? translated by Alfred John Church and...