As previously stated, units of the Roman Army were gradually withdrawn from Britain to fight on the Continent. As the domestic situation deteriorated, the ruling pro-Roman elite decided to leave the towns and make for their fortified villas in the country.
Although most of the fighting troops had been withdrawn, it's seems that some were left to put up a defense against the gangs of bandits and deserters, the Warbands of Scots-Irish,( the Del-Riata) and Picts along with bands of Franks and Frisians.
Addendum July 8th 2020:
As mentioned in a previous article my own belief is that the "Saxon" raiders could have been Frankish or Frisian Pirates.
The Franks and Saxons detested each other. There were Saxon Federated troops already in Britannia at this time. I have read that, there is very little archeological evidence of Saxon settlement in Britannia during this period, and prior to 450AD. Therefore I’m assuming that any Saxons, Angles or Jutes were posted within Roman military forts.
The Forces Involved.
This is a bit of a tough one. There is information available on regular units for this era but not actual numbers, so this is my best guess.
Cavalry;
There was only one formation that stayed in Britain. This was the Ala Petriana. It was based near Carlisle ( Luguvalium on the map ) at a fort on Hadrians Wall ( Uxelodunum ).
There was also a fort at Verbeia ( Ilkley) which contained a cataphract cavalry unit. This could have been a unit detached from the main Petriana Ala.
The original formation was 1000 men but by the time of the 4th century that number could have been half or less. My own estimate is 300 to 500 men, tending toward the lower figure. I also think this unit would probably have ended up at Eboricum ( York). There may have been other Cavalry formations but they were only stationed in Britannia for a short while.
When the unit first came to Britain they may have been composed of armoured cavalry. As time went on the armour may have become lighter in order to become more mobile. Also, in campaigning it may have been the experience that less armour was required against lighter armed opponents.
In regard to weapons, it seems that the cavalrymen were well trained in the use of the lance, spears, javelin and bow. Therefore any cavalry you have in your collection will fit the bill.
The Prefect of the Ala was the Senior Prefect within the Roman Army in Britain. Some of the cavalry unit may have been taken to Gaul but it is not known wether this transfer took place if at all
The Heavy Infantry.
In the early days of the Empire there were six Legions based in Britain and involved in campaigns against the tribes. These were;
2nd Legion Augusta,
2nd Legion Adiutrix,
6th Legion Victrix,
9th Legion Hispana,
14th Legion Gemini,
20th Legion Valeria.
Three of these Legions ( or sub-units of these formations ) were still in Britain during the 4th century;
The 2nd Augusta. Based at Rutupiae. ( Richborough ).
The 6th Victrix. Based at Eboricum. ( York )
The 20th Valeria. Based at Deva, (Chester ) with some units at Camuludunum. ( Slack near Huddersfield ).
Originally of 4/5000 men these unit numbers would have been changed under the Diocletion reforms. The original number was reduced to 2000 men per Legion. This number could have been weakened more by Imperial claimants taking troops back to Gaul.
The Auxilliaries;
Originally drawn from all over the Empire and coming in with the Legions, up to 30,000 Auxiliary infantry served in Britain. These were organised into Cohorts of 500 infantrymen and armed with bows, slings, javelin and spears. Most of these infantry were also withdrawn leaving roughly 7000 men still manning their posts.
Citizen Qualification:
This was a major influence on the organisation of the Roman Army. In 212AD all Freemen within the Empire became Citizens. The difference between Legionary and Auxilliary disappeared and every man was a " Peditatus"or Infantryman. The Cavalrymen were always known as Equites.
The Later Army.
The Army was now divided in half. One half was the Field Army ( the Commitatenses ) which engaged in mobile operations. The other half was the Limitanii. These were used as static units to defend the borders.
There has been a debate over the years about the quality and armament of these border troops, but recent thinking has decided that these men were just as well trained as the field troops.
Some of the Limitanii may well have been experienced veterans retired from the Field Army.
These men also had access to the equipment when required. On most occasions they went up against lightly armed raiders with at most a shield. Therefore, a shield and helmet were all that was needed. Body armour (mail or leather ) was available if more serious fighting was intended. The large heavy shield was dispensed with in favour of a smaller round or oval shield more suited for dispersed fighting in woodland.
Therefore all the Infantrymen of the 2nd, 6th and 20th would have been Limitanii style infantry. Their main weapon is still the famous Pilum, the weighted heavy javelin used by all Roman Infantry since the early days of the Republic. However this weapon was now gradually being replaced with the Verutum ( a spear that could be thrown or used in close combat ), and the Spiculum, an all-metal javelin similar to the pilum.
There was also the Plumbata or martiobarbouli This was a small weighted dart, 4 of which were clipped behind the shield.
The Peditus were also trained in the use of bows and slings. Therefore your Cohort could have four stands all armed differently.
Troop totals;
Taking into account the above numbers, the reforms and Rebellions I estimate 13,000 infantry and 1000 cavalry. I think the Cavalry would have been kept at full strength as long as possible. Without good quality remounts being available the Ala would have slowly lost its strength.
Note: Between 367AD and 372AD, Count Theodosius The Elder was made Comes Britannarium and sent to Britannia by the Emperor Valentinian with a force of 4 units. Not a great deal is known of the exact composition, but it was either Cohorts or Ala or a mix of both Cavalry and Infantry. As both types were of approximately 500 men, that would make this force about 2000 strong.
At one point Magnus, during 383 to 390, while still attempting to take the Purple, was forced to send back a Legion plus cavalry to Britannia. This force was led by the Comes Gallium with the name of Vallio. Although successful he was assassinated so that he could not threaten Maximus.
At this time the Penine and Welsh forts were abandoned, with the 20th Legion being withdrawn from Glevum. There is a possibility that Eboricum became more prominent as a central base for the Romano British forces.
Troop command.
During this era the Provinces were subdivided to reduce any Provincial Governers chances of gathering a large army. Next,command of army units were taken out of the hands of local Governors and retained within the Army. There were two Senior Commands in Britannia ;
The Dux Brittanarium; He commanded units in the North and East
The Comes Litoris Saxonici; The Count of the Saxon Shore. He commanded the units stationed in the South and South-East of the country.( The Romans may have used the word “ Saxon “ as a broad description for any Germanic tribes, therefore Frisian and Frankish pirates being “ Saxon” hence The Saxon Shore.)
The Dux Brittanarium was the Senior of the two. There are two that are known of;
Fullofaudes. He met his end during the Great Barbarian Conspiracy.
His replacement, Dulcitius carried on the command.
How long these two men were in charge during the 4th century is not known.
The Count of the Saxon Shore; one was Nectaridus. He was also killed during the Conspiracy but his replacement is unknown. When Theodosius the Elder came to Britannia he may have taken over command.
The troops themselves were organised into 500 man Cohorts led by a Prefect or Tribune. The word “ Cohort" was gradually changing to “ Numerus”.
Suggested scale of troops;
Using the Table Top Battles system;
1,000 cavalry = 1 point x 2 = 1 stand of cavalry @ 2 points.
13,000 infantry = 13 points x 2 = 26 points =
4 armoured infantry @ 3 points = 12 points.
4 stands of unarmoured infantry @ 2 points each = 8 points.
4 stands of unarmoured archers @ 1 point each = 4 points.
2 Command stands @ 1 point each = 2 points.
Total = 28 points.
The infantry composition can be changed by withdrawing the armoured infantry for lighter armed troops. The cavalry can be upgraded to 3points if you withdraw 1 General. The Cavalry always remains at one stand.
Alternatively; A stand is equal to roughly 25 to 75 men; with four stands equalling a unit. A 1 point stand equals 25 men. A 2 point stand equals 50 men. A 3 point stand equals 75 men.
As you can see by the photos the 4 stand unit is the one I am using ( the practical reason being, that you get a lot of plastic in a box!!) but I still use a mix of individual stands in an “ ad hoc” arrangement if required. The 3 point stand is the “ heaviest” available in Britannia in this Era.
That's the end of this chapter. The figures are 20mm Hat figures with some Newline designs 20mm metal. The map was hand drawn by myself with info gleaned from The Ordinance Survey map of Roman Britain.