Mars

Mars was Rome’s father. Through the Vestal Virgin Rhea Silvia, he sired Romulus and Remus, the twin founders of the city. Every Roman citizen descended, in the mythology, from Mars. This made Rome a city founded by the god of war, and the Romans took the implication seriously.

The Older Mars

Before Rome became a military power, Mars was an agricultural deity. Cato the Elder’s De Agri Cultura, written in the second century BCE, preserves a prayer to Mars for the protection of crops and livestock. The Arval Brethren, one of Rome’s oldest priesthoods, sang a hymn to Mars for the fertility of fields. The war function came later, layered over a god who guarded the boundary between cultivated land and the wild.

The Army’s God

Roman legions sacrificed to Mars before campaigns and after victories. The suovetaurilia, the triple sacrifice of a pig, a sheep, and a bull, was performed in his name to purify the army. His priests, the Salii, danced through Rome in March carrying sacred shields called ancilia. The shields were said to include one that fell from heaven. The Romans did not distinguish between religious ritual and military discipline. Mars occupied both.

March

The old Roman calendar began in March, Martius, making the war god’s month the start of the year. It was the month when military campaigns resumed after winter. The Campus Martius, the broad field along the Tiber, served as training ground, assembly place, and eventually the site of the most important public buildings of the late Republic and Empire. The field of Mars was where Rome did its business.