The Orb

The orb is a defensive postition in the shape of a circle taken by a unit in desperate straits. It allows for a reasonably effective defence even if parts of an army have been divided in battle and would have required a very high level discipline by the individual soldiers.

Repel Cavalry

The order to repel cavalry brought about a the following formation. The first rank would form a firm wall with their shields, only their pila protruding, forming a vicious line of glistening spearheads ahead of the wall of shields. A horse, however well trained, could hardly be brought to break through such a barrier. The second rank of the infantry would then use its spears to drive off any attackers whose horses came to a halt. This formation would no doubt prove very effective, particularly against ill-disciplined enemy cavalry.

Skirmishing Formation

The saw was opposite tactic to the wedge. This was a detached unit, immediately behind the font line, capable of fast sideways movement down the length of the line to block any holes which might appear to develop a thrust where there might be a sign of weakness. In the case of two Roman armies fighting each other in a civil war, one might say that the 'saw' inevitably was the response to a 'wedge' by the other side.

The skirmishing formation was a widely spaced line up of troops, as opposed to the tighter packed battle ranks so typical of legionary tactics. It allowed for greater mobility and would have found many uses in the tactical handbooks of Roman generals.

The Wedge

The wedge was commonly used by attacking legionaries, - legionaries formed up in a triangle, the front 'tip' being one man and pointing toward the enemy, - this enabled small groups to be thrust well into the enemy and, when these formations expanded, the enemy troops were pushed into restricted positions, making hand-to-hand fighting difficult. This is where the short legionary gladius was useful, held low and used as a thrusting weapon, while the longer Celtic and Germanic swords became impossible to wield.

The Tortoise (Testudo)

The tortoise was a essentially defensive formation by which the legionaries would hold their shields overhead, except for the front rows, thereby creating a kind of shell-like armour shielding them against missiles from the front or above.

The Seventh Formation

"If your forces are few and weak in comparison to the enemy, you must make use of the seventh formation and cover one of your flanks either with an eminence, a city, the sea, a river, or some protection of that kind."

When the Romans were outnumbered or had inferior troops, this was often the only hope for victory. The left flank was kept guarded by whatever protection was available. The right was protected by the light troops and cavalry. With both sides well covered, the army had little to fear from an attack.

The Sixth Formation

"He who cannot depend on either the number or courage of his troops, if obliged to engage, should begin the action with his right and endeavor to break the enemy's left, the rest of his army remaining formed in line perpendicular to the front and extended to the rear like a javelin. This is the sixth formation."

The sixth formation was similar to the second, with both having the right wing attacking the opponent's left from behind. In this attack, the enemy's left wing cannot be reinforced, for fear that it would leave an opening for the Romans to exploit.

The Fifth Formation

"He whose light infantry is good should cover his center by forming them in its front and charge both the enemy's wings at once. This is the fifth formation."

This was a variation of the fourth formation. Light infantry and archers were placed in front of the center, making it far less vulnerable.

The Fourth Formation

"The general who can depend on the discipline of his men should begin the engagement by attacking both of the enemy's wings at once, the fourth formation."

The fourth formation's main advantage was its shock value. The entire army was brought close to the enemy, whereupon both wings charged at the enemy. This would often surprise the opponent, allowing for a quick resolution. However, the attack split the army into three parts, so if the enemy survived the attack, the center of the Roman's forces was vulnerable, and the wings could be fought separately.

The Third Formation

"If your left wing is strongest, you must attack the enemy's right, according to the third formation."

The third formation was considered something of a desperation move, to be used only when your left wing, usually the weaker side, was stronger than your right. In this attack, the left wing, supplemented by the Roman's best cavalry, attacked the opponent's right wing, while their own right stayed back in relative safety.

The Second Formation

"He who judges himself inferior should advance his right wing against his enemy's left. This is the second formation."

The Second Formation

This formation, considered by some to be the best, took advantage of the fact that the left side of a soldier, and so the left side of the army was considered to be weaker, because it had to support the weight of the shield. The right wing moved around the opponent's left, and attacked from the rear. The left wing kept its distance, while the reserves supported the left wing or guarded against the enemy attacking the center.

The First Formation

"A general whose troops are superior in number and bravery should engage in the oblong square, which is 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 center.

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

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.

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.