Datis or Datus (Greek: Δάτης, Old Iranian: *Dātiya-, Achaemenid Elamite: Da-ti-ya), was a Median admiral who served the Persian Empire, under Darius the Great. He was an expert in Greek affairs and maintained connections with Greek officials. He is noted for his joint leadership with the younger Artaphernes of the Persian forces in the first campaign of the Persian Wars against the Greeks. His earlier career is not known.
|Born||Media, Achaemenid Empire|
Datis was one of the Persian commanders responsible for the siege of Naxos and the sacking of Eretria in 490 BC along with the Persian Immortals. He was also leader of the Persian assault force on the Athenians at the Battle of Marathon in the same year. Ctesias of Cnidus relates that Datis was slain at Marathon and that the Athenians refused to hand over his body, however this conflicts with Herodotus' earlier claim that Datis survived the battle 
Datis was originally called to duty alongside Artaphernes for the Greek invasion because Darius I had decided to temporarily relieve Mardonius of military service due to an injury he suffered in the Thracian campaign.
- Photius the Great, Excerpts of Ctesias' "Persica", Paragraph 22, available online at http://www.livius.org/ct-cz/ctesias/photius_persica.html
- Herodotus, Histories,I. 6.119; VI.94.