The entire foundation of Roman infantry tactics was the idea that by keeping troops in order, one could fight more effectively. Most military commanders of the day simply had their troops rush wildly at the enemy, relying on superior numbers, better soldiers, or luck to carry the day. The Romans realized that they could not always rely on these, so they turned to strategy. Each situation was handled differently, taking into account terrain, the type and strength of the opponent's troops, and the type and strength of the Roman's troops. Here are some common formations, and tactics that were organized by formations.
Typical Legion Formation
This was the default arrangement for a full legion in battle. The cavalry rode up front, on the sides where they could protect the flanks. In between them were two rows of five cohorts. The rightmost cohort consisted of ~1100 infantry and ~30 mounted troops, while the others contained ~550 infantry and ~65 cavalry. Behind the main group were seven units of light troops, followed by seven units of reserves.
Marching Formation
When the legion was in transit, a very different arrangement was required. The main part of the cavalry rode up front as a vanguard, followed by the infantry, in a long column of cohorts. Behind them came the army's baggage, servants, and vehicles, guarded by several units of cavalry. At the end came the best units of both infantry and cavalry, to defend against attacks from the rear. The lighter units were arranged around the edges to act as scouts.
Battle Formations
"A general whose troops are superior in number and bravery should engage in the oblong square, which is the first formation."
Marching Formation
The First Formation
This tactic, designed for level terrain, assumes that your wings are more powerful. Should the enemy make their way around your flanks, the reserves will be able to counter. Once their wings are vanquished, you may press the