There is nothing quite comparable in modern armies to the Roman standards, signa, except perhaps the regimental colours. They performed the function of being a recognition signal and a rallying point. Army units required a device to watch and follow in battle conditions and the soldiers also needed to recognize their own at a glance.
Roman standards were held in awe. They were symbols of Roman honour. So much so that to recover lost standards Roman leaders might engage on campaigns. For example a special campaign was launched against the Germans to recover the standards lost by Varus in the Teutoburger Wald.
The standards also played an important part in pitching and striking a camp.
The site for a camp being selected, the first act was to set up the standards by thrusting their pointed ends into the ground. When camp was struck the standards were plucked out by means of the large projecting handles. It would have been understood to be a serious omen had they stuck fast in the ground and the men might even refuse to move, saying that the gods meant them to stay there.
Standards also played an important part in the many religious festivals which the army scrupulously observed. On these occasions they were anointed with precious oils and decorated with garlands, special battle honours and laurel wreaths might have been added. It is hardly surprising that it has been said that the Army actually worshipped their standards.
In the line of battle the signa had key positions. This is clear from Caesar who often referred to the ante and post signani, these being the troops in front of and behind the standards.
Orders relating to standards were also given for movements, as in the African was, when during one engagement the troops became disorganized and were commanded not to advance more than four feet beyond their standards.
Another important function was in the systems of signals in the battlefield. Commands were relayed through the standard-bearers and the trumpeters, the cornicines. A blast from the cornu drew the soldiers’ attention to their standard, where it was carried they would follow in formation. A limited number of signals by up and down or swaying movements were indicative of pre-arranged commands to the ranks.
When one comes to the standards themselves and their various types and patterns throughout imperial times there are some serious gaps in current knowledge. It can though be assumed that animal standards were used by Roman legions from earliest times and that they gradually became rationalized.
The republican is reputed by the historian Pliny the elder to have had five standards, an eagle, a wolf, a Minotaur, a horse and a boar. Marius made the eagle supreme because of its close associations with Jupiter, and the remainder were relegated or abolished. In late republican times the eagle standard (aquila) was made of silver and a golden thunderbolt was held in the claws of the eagle., but later it was made entirely of gold and carried by the senior standard bearer, the aquilifer.
It was the eagle standard which bore the famous Roman abbreviation SPQR. The letters stand for senatus populusque romanus which means ‘the senate and the people of Rome’. Hence this standard represented the will of the Roman people and stated that the soldiers acted on their behalf. The abbreviation SPQR remained a potent symbol throughout the history of the empire, as the senate remained to be seen as (theoretically) the highest authority during the times of the emperors.
While the eagle was common to all legions, each unit had several of its own symbols. These were often associated with the birthday of the unit or its founder or of a commander under whom it had won a particular victory. These symbols were signs of the Zodiac. Thus the bull signifies the period 17th April to 18th May, which was sacred to Venus the goddess mother of the Julian family; similarly the Capricorn was the emblem of Augustus.
Thus, II Augusta, one of the British legions, displayed the Capricorn for as its name denotes it was founded by Augustus. Further II Augusta also bore symbols of Pegasus and Mars. That of Mars in particular more than likely signifying some oath taken to the god of war in times of peril.
The imago was a standard of special importance, bringing the emperor into a closer relationship with his troops. This standard bearing the image of the emperor was carried by the imaginifer. In later times it also had portraits of other members of the ruling house.
The aquila and the imago were in special care of the first cohort, but there were other standards for each century. The maniple was a very ancient division of the legion consisting of two centuries. And for this division, too, there was a standard. The Romans themselves seem to have no information about the origins of this standard and it was supposed to have derived from a pole with a handful of straw tied to the top.
The hand (manus) at the top of this standard had a significance, although it may not have been understood by the later romans themselves. Military salute ? Divine protection ? Below the hand is a crossbar from which could be hung wreaths or fillets and attached to the staff, in vertical array, are discs bearing numbers. The precise significance of these numbers is not understood but they might have indicated the numbers of the cohort, century or maniple.
The standard which most closely resembles the modern flag is the vexillum, a small square piece of cloth attached to a cross-bar carried on a pole. It is a type of standard more commonly born by cavalry, the senior standard bearer of an ala being known as the vexillarius Different coloured pieces of cloth could be hung from the vexillum, the red flag denoting that battle was about to begin.
Finally it should be noted that the standard bearers wore animal skins over their uniforms. This follows Celtic practice. The Suebi for instance wore boar masks. The heads of the animals were carried over the bearers’ helmets so that the teeth were actually seen on the forehead.