180 was a typo. I corrected above. Marian centuries had 80 men. A maniple had two centuries. 80 x 2 = 160.
The smallest unit in the roman army was the contubernium. A contubernium was a squad of 8 men, who lived together, worked together, trained together and fought together.
During the Polybian era eight contubernia were grouped into a century: 8 x 8 = 64. Some historians believe that the Centurion, Optio, and Signifiers (the NCO's) were originally selected from among the 64 four men of century. But it seems this practice eventually change so that at least the Centurion was a senior member with more experience.
Sixty in latin is Sexaginta. It is possible that a Senturion (with S) may have been a person in charge of Sixtyfour men... And eventually the term century was adopted to mean a unit of sixty four men.
Centuries worked in pairs, two centuries formed a maniple. A Polybian maniple had 64 x 2 = 128 legionaries (except for triariis). The senior of the two centurions would lead the maniple. The maniple, not the century, was the tactical unit of the roman legion.
Triariis were different. Many historians think that the tirarii maniple had only one century, instead of two.
Polybian Cohorts had one maniple of hastati, one maniple of principes, and one maniple of triariis. Hence a Polybian cohort would have 2H +2P +1T = 5 centuries or 5 *64 = 320. A cohort would also have a number of velites attached to it. Sources are not clear as to the exact number of velites attached to each cohort. Furthermore, I am not sure whether velites were considered legionaries.
The legion had 10 cohorts, so if you account for the fact that Triarii maniples had only one century, you get 3,200 heavy legionaries per legion. This number does not include velites and other supporting units.
Marian centuries had 10 contubernia per century. Hence each century grew from 64 to 80 men. It seems that during the Marian era, centurions were senior soldiers drawn from other units. I do not know whether the other NCO's were drawn from the ranks or were senior soldiers drawn from other units.
In any event, a Marian century had 80 foot soldiers. Marian Centuries paired up to form Maniples of 160 men. At some point, triariis were eliminated, and thereafter a cohort was formed by three maniples of 160 men each: 160 x3 =480. A Marian legion had 10 cohorts. 10 x 480 =4,800 legionaries.
I understand Marian legionaries did not serve as velites. At some point after the Marian reforms light infantry and skirmishing was left to the auxilia, which were not Roman citizens. Not so for siege weapons. When a Marian legion was equipped with scorpions, a number of men were drawn from each century to man the scorpions. I think the same was true for other artillery/siege platforms, but my memory is not clear on this point.
Keep in mind that all the above numbers are paper strength only. Particularly for a Marian Legions, where men served at 16 years (or more depending on the time period), actual strength must have been substantially lower than paper strength.
Two thousand years ago, Maniples of 120 - 160 men were the tactical units of the Roman army. These maniples of 120-160 men, resemble EB's tactical units (EB cohorts) in large or huge setting.
...in this particular sense you may say I "consider a cohort to be a maniple". However, you could say that I consider a maniple to be maniple, while others consider a maniple to be a cohort.![]()
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