William Smith,
A Smaller Dictionary of Greek and Roman Antiquities
“ The toga praetexta is said to have been derived from the Etruscans, and to have been first adopted, with the latus clavus [Clavus Latus] , by Tullus Hostilius as the royal robe, whence its use by the magistrates in the republic. The toga praetexta and the bulla aurea were first given to boys in the case of the son of Tarquinius Priscus, who, at the age of fourteen, in the Sabine war, slew an enemy with his own hand. Respecting the leaving off of the toga praetexta, and the assumption of the toga virilis, see Impubes and Clavus Latus. ”
