Roman Auxiliaries, cohors equitata proportions

[Alan Hamilton]

I am about to add one or two Cohors Equitata to my representative collection of Early Imperial Romans which for wargaming purposes I am using an approx 1:20 figure scale.  The proportion of cavalry to infantry is also important as I understand that there are different views on the strengths of the infantry and cavalry components and so I am seeking opinions.  My forces are based on the Romans in Britain and my preference would lie along the lines of a total strength of about 24-28 figures.  So far I have seen:

Cohors Equitata – 320 foot and 120 mounted which gives me 22 figures – 16 foot and 6 mounted

Cohors Equitata Quingenaria – 480 – 600 foot and 120 mounted which gives me 30 – 36 figures – 24 to 30 foot and 6 mounted

Cohors Equitata Milliara – 800 foot and 240 mounted which gives me 52 figures – 40 foot and 12 mounted

The last mentioned is a bit large for my wargames but would be impressive! There are no doubt other versions.

[willb]

Auxiliary cohorts were either Quingenaria or Milaria, 480 or 800 infantry respectively at full strength.  Cohors equitata added a portion of cavalry   Equitata units added 120 or 240 cavalry respectively.  The cavalry component appears to have been added to the infantry cohorts to help provide a patrol and scouting formation.  Source: Armies and Enemies of Imperial Rome by Phil Barker.  Note the cohort strengths correspond to the strengths of the cohorts in a legion.  800 for the first and 480 for the others.

There was a Cohors Dromedaria in Egypt that had 24 additional camel riders added to it.

I did find references to the smaller strength formation at a couple of pages at  https://www.wikia.org/      However, I am not sure how reliable the information at that site is and the source links listed on those pages are dead.  The total strength of 500 men may be due to the source’s belief that the cohort had 500 men in total.  Part of this may be due to the Romans having centuries of 80 men while the title indicates 100 men.

This page has an excerpt from a paper on auxiliary cohorts in Britain  https://www.jstor.org/stable/4435236?seq=1   It notes that five of seven Milaria cohorts were equitata and 31 of the 46 quingenaria cohorts were equitata.  The page shown there agrees with Barker’s numbers for the cavalry in the two types of cohorts and notes Cheeseman’s belief that they were only poorly trained infantry instead of a cavalry attachment.

 

[Mike Headden]

I think the references to 500 man units, etc. is indeed a misunderstanding of the size caused by taking the Latin names of units too literally.

Of course, in reality most would have been reduced by the “3D effect” – Disease, Desertion and Detachments!

 

There are 100 types of people in the world, those who understand binary and those who can work from incomplete data

[Alan Hamilton]

Interesting information and thanks.  However, do you have a primary source reference that the mounted contingent was “added” to the cohort?  If so from where did they come? I could not find it in the article quoted which discusses only differences between the two types of cavalry.  It also mentions that the mounted contingent is divided into turmae (cavalry designation) without a primary source reference.  Also the differential rates of pay might imply that the mounted men were infantrymen trained to fight mounted so get one and a half pay while the cavalry trooper from an ala with his greater skills gets double pay.

For example if we assume that the cohors equitata (note infantry designation) actually had 500 men (infantry cohort strength) and is divided into 6 centuries.  Then we assume that the mounted contingent is drawn from these centuries that would, on average, be 15 men from each century or just about 2 contubernia.   This would be similar to the eques legionis who were given infantry designations and commanded by a Centurion.

I may be entirely wrong.

[Mike Headden]

Centuries were nominally 80 strong. 10 contubernia of 8 men, who shared a tent. Strengths of between 60 and 80 are the actual norm. We have surviving unit returns showing how many troops there were and what they were doing (supposedly!). Strengths are often well below the nominal level.

A contubernium was also a quasi-marital relationship between a free citizen and a slave or between two slaves in ancient Rome. Make of that what you will 🙂

I assume the centurion and his optio would possibly add to that rather than be included in the 60-80.

Cohors equitata consisted of both foot and mounted auxilia. Quingenaria units would be 480 infantry and 120 cavalry in 6 centuria and 4 turmae respectively. They were one unit, though in battle the cavalry seem to have been brigaded together to form larger units, where possible. The cavalry didn’t “come from” anywhere they were an integral part of the unit.

The cavalry in the regular alae and those in the equitata units seem to have been equipped the same and used the same in battle. Both operating side-by-side.

An example would be Cohors Secunda Gallorum Veterana Equitata, stationed at the fort of Voreda, near Penrith. They were a quingenaria unit and it is suggested that in 178AD when they were awarded the Veterana title it was because they were the senior auxilia unit in Britannia.

 

There are 100 types of people in the world, those who understand binary and those who can work from incomplete data

[willb]

The last link I included in the previous post states the primary source is De Munitionibus Castrorum.  There are additional pages not shown which may include information on the actual strength of each unit.  Click on the view preview bar to see an enlarged version of the page.

The following is also from Armies and Enemies of Imperial Rome:  Auxiliary cavalry Alae were either 16 or 24  turmae of 30 men giving strengths of 480 or 720 respectively.  There was a very rare type known as Alae Peditata which had an unknown number of infantry attached.   Auxiliary cohorts were either 6 cohorts or ten cohorts of 80 men each.   Barker states that between the time of Julius Caesar and the Jewish revolt of 66 A.D. four turmae of 30 men were added to each legion along with a Decurio commanding each unit and a second-in-command.  Barker later notes that by the reign of Septimius Severus that legion cohorts had increased in strength to at least 550 men. Unfortunately, Barker had a tendency not to list his sources.

While the cohors milliara would provide eight 30 man turmae if they were drawn from the infantry centuria, the cohors quingenaria would not match this due to having six centuria.

This site give other possible strengths of cohorts depending on the number of men per century  https://www.futurelearn.com/courses/hadrians-wall/0/steps/5103  but also indicates that the cavalry are in addition to the infantry and not drawn from the infantry cohorts based on the strengths given.

[Alan Hamilton]

Thanks a lot for your detailed and very useful answers.  It is now making sense to me. Unfortunately for me, I now realise that my cavalry ala is under strength.

Taking your guidance I am going for my cohors equitata as a Prefect, 24 infantry (commanded by a Centurion) and 6 cavalry (commanded by a Decurion).

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