The Roman Army, 31 BC–AD 337: A Sourcebook

The army in the field 83
bordering on this are the Iberians and Albanians and other kings who
were protected against external regimes by the greatness of our power.
Rhoemetalces and the sons of Cotys ruled Thrace, while the bank of
the river Danube was guarded by two legions in Pannonia and two in
Moesia. A further two legions were stationed in Dalmatia,
geographically behind the other four, and could be summoned from
close by if Italy needed rapid help. Rome however had its own garrison
in the form of three urban and nine praetorian cohorts, recruited mainly
from Etruria and Umbria or the old territory of the Latins, and the
ancient Roman colonies. In suitable locations in the provinces were
stationed allied ships, auxiliary cavalry alae and infantry cohorts,
virtually equivalent in strength to the legions. But it is difficult to trace
them all since they were moved to different locations as circumstances
demanded, and their numbers increased or decreased from time to time.
Tacitus is referring to AD 23, when the Pannonian Legion IX Hispana had
been transferred to Africa to help put down the rebellion of Tacfarinas.
143 Dio (2nd–3rd C.AD), 55. 23
Twenty-three, or as some argue, twenty-five legions were being
maintained at this time (after AD 9). At the present moment only nineteen
of them still exist: the second, Augusta, with its winter quarters in Upper
Britain; the three third legions—the Gallica in Syria Phoenice, the
Cyrenaica in Arabia, the Augusta in Numidia; the fourth, Scythica, in
Syria; the fifth, Macedonica, in Dacia; two sixth legions, of which one,
Victrix, is in Lower Britain, and one, Ferrata, in Judaea; the seventh,
generally called Claudia, in Upper Moesia; the eighth, Augusta, in Upper
Germany; the two tenth legions, one, Gemina, in Upper Pannonia and
one (Fretensis) in Judaea; the eleventh, Claudia, in Lower Moesia; for
two legions were named after Claudius in this way because they had not
fought against him in the revolt of Camillus; the twelfth, Fulminata, in
Cappadocia; the thirteenth, Gemina, in Dacia; the fourteenth, Gemina,
in Upper Pannonia; the fifteenth, Apollinaris, in Cappadocia; the
Twentieth, named Valeria Victrix, in Upper Britain. These then in my
view were the troops Augustus took over and kept, along with those of
the legion called the twenty-second and stationed in Upper Germany,
even if this legion was certainly not called Valeria by everyone and does
not employ this name now. These are the legions that are still in existence
out of those of Augustus. As regards the remainder, some were completely
disbanded, others were joined with other legions by Augustus himself
and by other emperors, as a result of which they have the name Gemina.
Since I have once been led into discussing the legions, I shall describe