Chiliarch is a military rank dating back to antiquity. Originally denoting the commander of a unit of about one thousand men (a chiliarchy) in the Macedonian army, it was subsequently used as a Greek translation of a Persian officer who functioned as a kind of vizier and of the Roman military tribunes. It has subsequently been used for other similar ranks and positions in other armed forces. Name The English term chiliarch was borrowed from Latin , a transcription of Greek khilíarkhos () and khiliárkhēs (), both meaning "commander of a thousand". The name has also occasionally been written as chiliarcha, chiliarchus, or chiliarchos or calqued as thousandman. The chiliad or chiliarchy controlled by a chiliarch derives from Latin , from Greek khiliarkhía (). Ancient Macedon and Persia In the Ancient Macedonian army, a chiliarch was the commander of a 1024-strong chiliarchy or of the and the hypaspists heavy infantry, subdivided into 64 files () of 16 men each. At the same time, officers known as pentakosiarchs ("commanders of 500") are also mentioned alongside the chiliarchs under both Alexander the Great and in the Ptolemaic armies, apparently as subordinate officers. In addition, the title of chiliarch was used as the Greek equivalent of the Achaemenid Persian title (also transliterated ). The Achaemenid army was organized on a decimal basis, and the was the commander of the (, "apple-bearers"), the 1,000-strong personal bodyguard of the Achaemenid kings. The latter often played a role analogous to that of a majordomo or vizier in later times. The Persian office was in turn adopted by Alexander the Great, and first awarded to Hephaestion and after Hephaestion's death to Perdiccas. Likewise, Antipater shortly before his death named Polyperchon as , but then named his own son Cassander as chiliarch, and thereby "second in authority" according to Diodorus Siculus (XVIII.48.4–5). This Persian-inspired office did not survive into subsequent Hellenistic practice. However, it was revived by later Iranian dynasties: while its existence in the Parthian Empire is unclear, it was certainly in existence in the 3rd century under the Sasanian Empire (Middle Persian: or ). According to the 5th-century Armenian historian Elishe, it was equivalent to or prime minister. From Persian, the term also passed into Armenian as and . Roman and Byzantine Empires Later Greek authors employed the term chiliarch for the Roman military tribunes, with the in particular rendered (). In the Byzantine Empire, the