A Dictionary of Greek and Roman Antiquities (1890)
William Smith, LLD, William Wayte, G. E. Marindin, Ed.

DECEM PRIMI

1. The Ten First of the Roman Senate were originally the heads of the decuries into which the senate of one hundred was divided. They took the office of interrex by turns, and are mentioned in that capacity at the first interregnum, on the death of Romulus (Liv. 1.17; cf. Dionys. A. R. 2.57). When subsequently the representatives of the Tities and Luceres were admitted into the senate, the Ramnes with their decem primi retained for some time their precedence over the other two tribes, and gave their votes first (Plut. Num. 3; Dionys. A. R. 2.58, 3.1). The first in rank among them was the princeps senatus, who was appointed by the king, and was at the same time custos urbis (Dionys. A. R. 2.12; J. Lydus, de Mens. 1.19). In the early republican period the decem primi seem to have been the consulars of the greater houses in order of seniority, then those of the lesser houses. The Ten First, who as ambassadors from the patricians concluded the treaty with the plebs on Mons Sacer, were all consulars (Niebuhr, Rom. Hist. 1.305, 340, 2.115 f., E. T.). Soon after the commencement of the republic they lost the exclusive privilege of the interregnum [INTERREX].

When the censors acquired the power of nominating the senators from among qualified persons, the decem primi were simply the first ten named by them: this choice was usually exercised according to merit, and a man who was generally acknowledged as the first Roman of his time was tolerably certain to become princeps senatus, and to retain the dignity for life. Valerius Corvus, the two Fabii Maximi, Rullianus and Cunctator, L. Aemilius Paullus, and the two Africani, all seem to have enjoyed this honour. The censors were often partial and passionate in the exercise of their almost irresponsible authority; but even the memorable quarrel between Livius Salinator and Claudius Nero did not prevent their giving the first place in the senate to Fabius Cunctator (Liv. 29.37.1).

2. In municipal senates we constantly find a committee, generally of ten, sometimes of a greater or less number, chosen (apparently by the decurions themselves) out of the larger body. In Italy this institution can be traced very far back: we find it in Latium as early as the great Latin war of 340 B.C. (Liv. 8.3.8); in the disaffected Latin colonies at the time of the second Punic war (id. 29.15.5); at Ameria in Cicero's time (pro Rosc. Am. 9.25); Antonius, quartered in Campania, “evocavit litteris e municipiis decemprimos et IIII. viros” (ad Att. 10.13 init.). Beyond Italy we find decem primi at Centuripae (in Verr. 2.67.162), quinque primi at Agyrium (ib. iii, 28.68), quindecim primi at Massilia (Caes. B.C. 1.35).

3. Wherever there was an ordo, Roman organisation seems to have involved the appointment of ten, or sometimes six, primi. Below the senatorian rank we find them among apparitores, lictores, and praecones (Mommsen, Staatsr. i.2 328, 340, 348); in priestly colleges (C. I. L. 6.2010; cf. the seviri under AUGUSTALES p. 258 b); and among the domestici or body-guards of the later empire (Cod. Theod. 6.24). The notion of so late a writer as J. Lydus (de Magistr. 1.46), that legionary officers were anciently so called, can hardly be accepted in default of better evidence. (Marquardt, Staatsverw. i.2 213 f.; Humbert, in D. and S.)

[W.W]