Military symbols of ancient Romans

Insigna: it was a sign distinguishing a company of the army. It was made by a pole with a drape, usually red, put on its final part. At the end of the pole there was a sculpture of an animal, representing the company. The animals used were topically ferocious ones, such as lion, panther or eagle.
The insigna was used to lead the soldiers, showing them where to move along  the battlefield.

The eagle: The eagle with the open wings and the right turned head was the symbol of the roman empire. It was carried by the soldier called "aquilifer", who had to defend it. He had to be ready to die rather than letting the enemy take it. In fact, the loss of the eagle was considered even worse than to lose the battle.

The vexillum: it was a red squared standard with inscribed the name or the symbol of the legion or of the cohort. The soldier who carried it was named vexillifer. The symbols of the legions and cohorts were usually the same kind of animals used for the insigna. Also the function of the vexillum was the same.

The signum: it was the standard of each manipolum (a unite made by 2 centuria) and each centuria (military unit of about 100 men). It was a pole with the final part decorated with a spearhead or a open hand. Along the pole there were, as decorations, garlands and metal discs; the number of the manipolum and the centuria; military decorations and other typical informations about the unit. The soldier who carried it was called signifer. The function of the signum was the same as the vexillum.

Immago: it was a representation of the Emperor, a sculpture or a high relief, carried by a soldier, the immaginifer. This was done to remember to the soldiers the link with the Emperor.