Mars

Mars was the Roman god of war, second only to Jupiter in the Roman pantheon. Unlike his Greek counterpart Ares, who was despised even by the other Olympians, Mars was revered — the Romans considered him the father of Romulus and Remus, and therefore the divine ancestor of Rome itself. His name likely derives from an older Italic deity, Mamers or Mavors, though the ultimate etymology remains disputed.

The Babylonians had already associated the red planet with war and destruction, calling it Nergal after their god of death. The Greeks named it Ares. When the Romans looked up and saw that rusty glow — the result of iron oxide on the planet's surface — they too saw blood and battle. Mars became the planet's name across the Latin-speaking world and, eventually, across modern astronomy.

From Mars came March, the first month of the old Roman calendar, when military campaigns resumed after winter. The Campus Martius — Field of Mars — was the open area outside Rome's walls where soldiers drilled and armies mustered. Martial, meaning 'relating to war,' entered English in the 1300s through Old French. Martial law, martial arts, court-martial — all descend from the war god's name. Even the word Martian, for a hypothetical inhabitant of the planet, carries the echo of divine violence.

When Percival Lowell peered through his telescope in the 1890s and thought he saw canals on Mars, he imagined a dying civilization struggling to irrigate a desiccated world. The god of war's planet became a place of tragic intelligence. H.G. Wells then reversed the fantasy in 1898: in The War of the Worlds, Mars attacked Earth. The planet named for war became, in fiction, the origin of war.