These military terms had different meanings at different periods.
1. In the original constitution of the Roman army, each legion of citizens
was accompanied by a body of 300 equites
; 2.24, 3;
6.20, 9). These were drawn up on the flanks of the infantry, and hence were
(cf. Cincius in Gel. 16.4.6
, alae dictae
exercitus equitum ordines, quod circum legiones dextra sinistraque,
tanquam alae in avium corporibus, locabantur
2. When, at a later date, the socii
required to contribute a contingent to the Roman army, the Roman legions
were placed in the centre of the line of battle, and the allies formed the
wings. Hence the allied troops, both cavalry and infantry, were sometimes
and we find mention, not only of equites,
but also of cohortes alares or
were commonly grouped together as the dextera
and the sinistra ala
although these terms did not always correspond to their position in the line
of battle (id. 27.2).
3. After the franchise had been extended to the whole of Italy, and thus all
Italian troops were included in the legions, the term alarii
was transferred to the foreign troops (auxilia
) serving along with the Roman armies. Thus
1.73) distinguishes the cohtortes alariae
from the legionariae
(cf. B. G.
4. Under the Empire, the word ala
denotes “auxiliary cavalry,” the term cohortes
being used without any epithet to denote
“auxiliary infantry,” as contrasted with the legiones.
Thus Tacitus (list.
4.18) mentions the ala Batavorum,
&c., and many others are known to us from inscriptions (cf. Henzen,
c. viii. p. 131). Sometimes a body of
horse was named from the officer who had first raised it, or who commanded
it at the time: cf. ala Liliana
(Tac. Hist. 1.75
), ala Auriana
(ib. 3.5). The
was originally divided into the
each containing three decuriae.
But at a later time the ala
was either miliaria or
in the former case there were 24 turmae,
in the latter 16, besides various officers (Hygin.
16, 23, 30; cf. Henzen,
Annal. dell' Inst.
1860, p. 71).