Cohors
A division of the Roman army. (See
Exercitus).
In the republican age the word was especially applied to the divisions contributed by the
Italian allies. Down to B.C. 89, when the Italians obtained the Roman citizenship, they were
bound to supply an infantry contingent to each of the two consular armies, which consisted of
two legions apiece. This contingent numbered in all 10,000 infantry, divided into: (
a) 20
cohortes of 420 men each, called
cohortes alares, because in time of battle they formed the wings (
alae) of the two combined legions; (
b) four
cohortes extraordinariae, or select cohorts of 400 men each.
From about the beginning of the first century B.C., the Roman legion, averaging 4000 men,
was also divided into ten
cohortes, each containing three
manipuli or six
centuriae. In the imperial times, the auxiliary
troops assigned to the legions stationed in the provinces were also divided into cohorts (
cohortes auxiliariae). These cohorts contained either 500 men (=5
centuriae), or 1000 men (=10
centuriae). They consisted
either entirely of infantry, or partly of cavalry (380 infantry+120 cavalry; 760 infantry+240
cavalry). For the commanders of these cohorts, see
Praefectus. The troops stationed in Rome were also numbered according to
cohorts.
1.
The
cohortes praetoriae, originally nine, but afterwards ten in
number, which formed the imperial body-guard. Each cohort consisted of
1000 men, including infantry and cavalry. (See
Praetoriani.) The institution of a bodyguard was due to Augustus, and was a
development of the
cohors praetoria, or body-guard of the republican
generals. Its title shows that it was as old as the time when the consuls bore the name of
praetores. This
cohors praetoria was originally
formed exclusively of cavalry, mainly of equestrian rank. But towards the end of the
republican age, when every independent commander had his own
cohors
praetoria, it was made up partly of infantry, who were mainly veterans, partly of
picked cavalry of the allies, and partly of Roman
equites, who usually
served their
tirocinium, or first year, in this way.
2.
Three, and in later times four,
cohortes urbanae, consisting each of
1000 men, were placed under the command of the
praefectus urbi. They had
separate barracks, but ranked below the body-guard and above the legionaries.
3.
Seven
cohortes vigilum, of 1000 men each, were under the command of
the
praefectus vigilum. These formed the night police and fire brigade,
and were distributed throughout the city, one to every two of the fourteen
regiones. See
Vigiles.
