How did Mars and its moons get their names? The Romans knew of seven bright objects in the sky, the sun, the moon and the five brightest planets. They named them after their most important gods. The Romans were great soldiers and thought Mars, the god of war, was very important. Mars, the red planet, was named after this god of war. According to Roman myth, Mars rode on a chariot pulled by two horses named Phobos and Deimos (meaning fear and panic). The two small moons of Mars are named after these two mythical horses.