By the time of the Byzantine era, the surviving roman empire, the roman army began a standard war layout. There were two wings, of 400 men each, one to the left and one to the right. These wings were in front of and to the right or left of the fighting line.  Behind the wings and to the side of the fighting line were flanks, a group of 200 men each. The fighting line, 15000 men, was front and center with a supporting line right behind with 13000 men. At the very back of it all were two reserves of 500 men each.

 

Left Wing                                                                                                          Right Wing

400 Men                                                                                                       400 Men

 

Flank                                   Fighting Line                                    Flank

200 Men                                 

 15000 Men                                    200 Men

 

Supporting Line

13000 Men

 

Reserve                                                               Reserve

500 Men                                                                  500 Men

           

 

    The following are seven specific instructions by Vegetius regarding the layout before battle (taken from http://www.roman-empire.net/army/tactics.html)

 

1	On level ground the force is drawn up with a centre, two wings and reserves in the rear. The wings and reserves must be strong enough to prevent any enveloping or outflanking manoeuvre.
2	An oblique battle line with the left wing held back in a defensive position while the right advances to turn the opponent's left flank. Opposition to this move is to strengthen your left wing with cavalry and reserves, but if both sides are successful the battle front would tend to move in an anti-clockwise direction, the effect of which would vary with the nature of the ground. With this in mind it is as well to attempt to stabilize the left wing with the protection of rough or impenetrable ground, while the right wing should have unimpeded movement.
3	The same as No 2 except that the left wing is now made the stronger and attempts a turning movement and is to be tried only when it is known that the enemy's right wing is weak.
4	Here both wings are advanced together, leaving the centre behind. This may take the enemy by surprise and leave his centre exposed and demoralized. If, however, the wings are held, it could be a very hazardous manoeuvre, since your army is now split into three separate formations and a skillful enemy could turn this to advantage.
5	The same tactic as No 4, but the centre is screened by light infantry or archers who can keep the enemy centre distracted while the wings engage.
6	This is a variation of No 2 whereby the centre and left wing are kept back while the right wing attempts a turning movement. If it is successful, the left wing, reinforced with reserves, could advance and hop to complete the enveloping movement which should compress the centre.
7	This is the use of suitable ground on either flank to protect it, as suggested in No 2

  

           In 350 AD the roman's started to leave Britain. No one knows for sure why they started to leave. Some believe the legionaries were call off to help secure other regions of Rome, in short, Rome was too big and couldn’t keep every one happy and under control. A similar theory by Adam Hart Davis is that “all control from the center, Rome, had dried up. No more sensible orders were coming out. Most of the ‘Roman’ soldiers stationed in Britain were from Spain, North Africa, Romania, and they were fed up with being in the remote, cold, inhospitable country. When the orders stopped coming in, they decided they’d rather go home.”

            In the Northern part of Britain, the roman Emperor Antoninum Pius, ordered his legionaries to build a wall to defend against the barbarians of Scotland. This wall is called the Antonine Wall. The barrier consisted of a line of forts and fortlets connected by a constant rampart wall and ditch. The wall ran for 39 Miles or 72.228 KM. That’s the same distance from Courtenay to Parksville.