Hesiod, Theogony 933 ff (trans. Evelyn-White) (Greek epic C8th or C7th B.C.) :
“Also Kytherea [Aphrodite] bare to Ares the shield-piercer Phobos (Panic) and Deimos (Fear), terrible gods who drive in disorder the close ranks of men in numbing war, with the help of Ares, sacker of towns.”
Mars, in Latin, and Ares, in Greek, are the names of ancient war gods. While the Greeks were not fond of their version, Ares, the Romans respected Mars (Mavors or Mamers) who is also an old Italian fertility god, known as Gradivus (the strider). Mars is the father of Rome’s founding father, Romulus, and his twin, Remus.
A colorful story about Ares/Mars and Aphrodite/Venus tells of their dalliance and embarrassing discovery, possibly resulting in her divorce from the husband she heartily disliked (Hephaestus).
She bore to the war god a daughter Harmonia (harmony) (important in the stories of the founding of the Greek city of Thebes as Cadmus’ wife), a son named Anteros (avenger of unrequited love), and twin boys Phobos and Deimos (Panic and Fear). Unlike harmony and requited love, panic and fear were suitable companions and charioteers for the war god.
The satellites of Mars are thought to have been asteroids.