BULLA, a kind of ornament worn about the neck, much in use among the ancient Romans. Whittaker, in his History of Manchester (vol. i. p. 79), is of opinion that bullæ were originally formed of leather among all ranks of people; and it is certain that they continued so to the last among the commonalty. He also imagines that at first the bulla was intended as an amulet rather than an ornament. Pliny refers the origin of the bulla to the elder Tarquin, who gave one along with the prætexta to his son, because at the age of fourteen he had killed an enemy; and in imitation of him it was afterwards assumed by other patricians. Some, however, affirm that the bulla was given by that king to the sons of all the patricians who had borne civil offices; whilst others allege that Romulus first introduced the bulla, and gave it to Tullus Hostilius, the first child born after the rape of the Sabines. The form of the bulla was generally circular. As the wealth of the state and the riches of individuals increased, the young patrician distinguished himself by a bulla of gold, whilst the common people wore the amulet of their ancestors. The bulla was laid aside at the same time as the prætexta, and consecrated to the Lares. Bullæ were not only hung round the necks of young men, but also on the foreheads of horses, and were sometimes allowed even to statues; whence the phrase statuæ bullatæ.
Bulla was also the denomination given to divers other metallic ornaments made after the same form. Such were the decorations used by the ancients on their doors and girdles. The bullæ of doors were large-headed nails or studs, carefully brightened or polished. The doors of temples were sometimes adorned with golden bullæ. By such door-studs were indicated which days were fasti and which nefasti.