Caracalla in in Harpers Dictionary of Classical Antiquities

A Gaulish outer garment resembling the Roman lacerna (q. v.), and first introduced at Rome by the emperor Aurelius Antoninus Bassianus, who compelled all plebeians who came to court to wear it, and hence received the name Caracalla, by which he is best known in history (Aurel. Vict. Epit. 21). In its longer form it came in later times to be worn by the clergy under the name of cassock (sottana, soutane). Like the lacerna, it was furnished with a cowl or hood (cucullus).