Unit Insignia

Marius introduced other innovations meant to boost morale and increase esprit de corps.  Each unit had its own flags (vexilla) and insignia (signa), usually signs of the zodiac or divine effigies. On each legion Marius bestowed a permanent number and its own unit.  Also given to the legion was its standard atop which sat a eagle � the bird of Jupiter and symbol of Rome. 

The legionary tandard was to become forever, the symbol of Rome's military prowess and her imperium.   The standard was composed of a silver eagle with outstretched wings,  at its feet was a golden thunderbolt. Below that were the letters SPQR (Senatus Populusque Romani, "the Senate and the Roman people").   The standard was endowed with religious sanctity and anointed with precious oils, decorated with garlands and crowned with laurels. Sacrifices were offered to it and oaths sworn before it. The standard had its own shrine in the center of the camp, not far from the legatus' (legion commander) tent. In battle the eagle was carried in the front line by the aquilifer, chosen because he was the best man in the legion. He wore a wolf or lion skin as a mark of his distinction and was expected to keep the standard safe.  No greater disaster could fall on a legion than the loss of its eagle as illustrated by the stress contemporaries laid on winning back the eagles lost by Varus in the Teutoberger Forest.

In addition to providing a source of esprit de corps, the standards also served more practical functions as rallying points for the men.  Their position also served as a way of indicating the position of the legion on the battlefield to the general and his subordinate commanders.