Salii, the "dancers," an old Italian priesthood, said to have been instituted by Numa for the service of Mars, although later tradition derived them from Greece. They were originally twelve in number, called Salii Palatini to distinguish them from a second college of twelve, Salii Agonales or Collini, said to have been added by Tullus Hostilius; the Palatini were consecrated to Mars, the Collini to Quirinus. All the members were patricians, vacancies being filled by co-optation from young men whose parents were both living; membership was for life, subject to certain exceptions. The officials of the college were the magister, the praesul, and the vates (the leaders in dance and song) .
Each college had the care of twelve sacred shields called ancilia. According to the story, during the reign of Numa a small oval shield fell from heaven, and Numa, in order to prevent its being stolen, had eleven others made exactly like it. They were the work of a smith named Mamurius Veturius, probably identical with the god Mamers (Mars) himself. These twelve shields (amongst which was the original one) were in charge of the Salii Palatini. The greater part of March (the birth-month of Mars), beginning from the 1st, on which day the ancile was said to have fallen from heaven and the campaigning season began, was devoted to various ceremonies connected with the Salii. On the 1st, they marched in procession through the city, dressed in an embroidered tunic, a brazen breastplate and a peaked cap; each carried a sword by his side and a short staff in his right hand, with which the shield, borne on the left arm, was struck from time to time. A halt was made at the altars and temples, where the Salii, singing a special chant, danced a war dance. Every day the procession stopped at certain stations (mansiones), where the shields were deposited for the night, and the Salii partook of a banquet (see Horace, Odes, i. 37.2). On the next day the procession passed on to another mansio; this continued till the 24th, when the shields were replaced in their sacrarium. During this period the Salii took part in certain other festivities: the Equirria (Ecurria) on the i 4th, a chariot race in honour of Mars on the Campus Martius (in later times called Mamuralia, in honour of Mamurius), at which a skin was beaten with staves in imitation of hammering; the Quinquatrus on the 19th, a one-day festival, at which the shields were cleansed; the Tubilustrium on the 23rd, when the trumpets of the priests were purified. On the 19th of October, at the Armilustrium or purification of arms, the ancilia were again brought out and then put away for the winter. The old chant of the Salii, called axamenta, was written in the old Saturnian metre, in language so archaic that even the priests themselves could hardly understand it.
See Quintilian, Instit. i. 6.40; also J. Wordsworth, Fragments and Specimens of Early Latin (1874). The best account of the Salii generally will be found in Marquardt, Romische Staatsverwaltung, iii. (1885) PP. 427-438.