Mars Before He Was God of War

March opens the year.

In the oldest Roman calendar — the calendar attributed to Romulus, which had ten months beginning in March and ending in December — March was the first month. The year began when the ground thawed and the Roman people could march out to do the two things that defined their spring: fight and farm. The timing is not coincidental. In the agricultural economy of early Latium, both activities happened in the same season, with the same men, using many of the same disciplines: preparation, resource-gathering, the organized labor of a community directed at a goal.

Mars governs both.

The oldest prayer of the Arval Brothers — the ancient priestly college dedicated to the fertility of the fields — invokes Mars directly: Help us, Mars! (Enos Lases iuvate — Help us, Lares — shifting between Mars and the ancestral Lares in a way that reveals the original identity: Mars as protective ancestral force of the Italian land, the deity who keeps the boundaries of fields against blight, against flood, against the predatory animals and predatory people who threaten the harvest.)

The Romans knew this older Mars. They did not discard him when the city’s needs made him primarily a god of war. They layered the martial Mars on top of the agricultural Mars and kept both active.

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The Salii dance his weapons through the streets.

In March and October — the opening and closing months of the military season — the twelve priest-dancers of Mars called the Salii put on their archaic armor: pointed bronze helmets, short military tunics, shields, and carry the sacred ancilia — the shield of Mars that fell from heaven in the reign of Numa Pompilius, plus eleven bronze replicas made to match it. They leap through the streets of Rome, stopping at prescribed points to sing the Carmen Saliare — the ancient hymn in an archaic Latin so old that even the Romans of the late Republic could not translate all of it.

The dance is a rite of military consecration: the army’s season is opened by the god’s armed priests dancing through the city that will send soldiers out in the god’s name. At the end of October, the same priests dance to close the season, the shields are stored until the next spring, and the army rests.

The word salio — to leap — gives the Salii their name. The leap is their ritual act, and it is also Mars’s characteristic motion: the spring, the bound forward, the explosive kinetic energy of the season’s beginning.

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He is the father of Romulus and Remus.

The story insists on this. Rhea Silvia, the Vestal Virgin, conceived her twins not by human agency but by the presence of Mars in the sacred grove — some versions say she fell asleep there and felt a divine presence, some say the god appeared to her as a man. The result is twin sons of a war god, conceived in a sacred place, exposed on a river, suckled by a wolf, and destined to found a city that becomes the dominant military power in the Mediterranean world.

The divine paternity is not incidental. It explains Rome. If Rome’s founder was the son of Mars, then Roman martial discipline is not merely cultural — it is genealogical, divine, the inheritance of the god’s own nature flowing through the founding family into the people. When Roman soldiers march into battle, they are in some sense continuing what their divine ancestor began in the grove with the Vestal.

Mars is also the protector of Rome in a personal way that Jupiter is not. Jupiter is universal — he governs all peoples, rewards the just, punishes the impious regardless of nationality. Mars has a preference. He is Romulus’s father. He is the Roman people’s divine grandfather. He watches his descendants with the particular attention of a god who has skin in the game.

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The Campus Martius — the Field of Mars — is the flat ground beside the Tiber where the army musters.

It is outside the pomerium, the sacred boundary of the city, because armies are not permitted inside the city limits in peacetime. The army assembles on Mars’s ground before crossing into Jupiter’s city. The field where the comitia centuriata — the assembly that elected Roman magistrates and passed laws — met is also the field where the army trained. The civic and the military share the same space, the field of the god who is both.

The Romans eventually built his temple there — the Temple of Mars Ultor, Mars the Avenger, built by Augustus to fulfill a vow he made before the battle of Philippi. The man who avenged Julius Caesar’s murder built his temple on the Field of Mars, and the temple contained the Eagle standards recovered from the Parthians, and statues of the Julian family, and a cult image of Mars in full armor.

But the prayers of the Arval Brothers were older. Help us, Mars! — the old cry of the farmers, asking the boundary-protector to keep the harvest safe. The farmers were still there, under the marble.