Chiliarch (from , chiliarchos/chiliarches, meaning "commander of a thousand") is a military rank dating back to Antiquity. The term was first used by Ancient Greek writers to render the Persian title hazarapatish, commander of 1,000 men in the Achaemenid Empire's army. In addition, the title was used for an officer who played an important role in the Achaemenid court, the commander of the 1,000-strong personal bodyguard of the Achaemenid kings, the melophoroi, drawn from the ranks of the Immortals. The latter often played a role analogous to that of a vizier in later times.