Cohorts (Latin cohors) - a tactical unit of the Roman army, which consisted of the legion. The literal translation from Latin is "fenced place". After the introduction of cohort tactics in the Roman army, the legion began to consist of 10 cohorts.
In the Third Punic War, one cohort included 2 manipuli. In this regard, each row consisted not of 10 maniples, but of 5 cohorts with corresponding intervals.
By August remained the same system of 10 cohorts in the legion, but the composition of the cohort changed: now it included 555 infantry and 66 horsemen. In addition, the first cohort began to include twice the number of warriors.
When the legion was formed up in battle, 10 cohorts were now placed in 2 ranks, with 5 cohorts each. On the right wing of the front rank was the first cohort, and to the left of it, by ordinal number, in the first row were 2-5 cohorts. Right behind them, similarly, were cohorts 6-10. The cohort number also indicated its strength — the most experienced and well-equipped fighters were in the first cohort, and the least - in the tenth. This order of battle existed before the time of Trajan and Hadrian. Due to clashes with new opponents, Rome again switched to a combat formation without gaps, and reserve combat reinforcements were placed behind the battle line.
Each of the three ranks of the cohort was called acies, the first lines of these ranks were the first rank (prima acies), the second and third were respectively secunda and tertia acies. At the same time, the series themselves were specified by the designations dextra, media and sinistra acies. Cohort soldiers could be called cohortalis. The first cohort of each legion enjoyed the greatest honor and military privileges, as it contained the primipil and aquila -the main relic of the legion.
In addition to the classic legion cohorts, there were also: