Battle of Gaugamela main Persian infantry was poorly trained and equipped in comparison to Alexander's pezhetairoi and hoplites. The only respectable infantry Darius had were his 2,000 Greek hoplites and his personal bodyguard, the 10,000 Immortals. The Greek mercenaries fought in a phalanx, armed not with a heavy shield but with spears no longer than three metres, while the spears of the Immortals were two metres long. Among the other Persian troops, the most heavily armed were the Armenians, who were armed the Greek way and probably fought as a phalanx. The rest of Darius' contingents were much more lightly armed; the main
Thracian language (meaning "up") and based on several Thracic items, would have meant "upon", "up", and "Utaspios" is theorized to have meant "On horse(back)", parallel to ancient Greek "ephippos (epi-hippos)". The early Indo-European languages had more than one word for horse; for example Latin had "equus" from PIE "*ekwo-" and "mannus" ("a pony") from another IE root, later receiving "cabalus" as a loanword. In many cases in current Thracology, there is more than one etymology for a Thracian lexical item. For example, Thracian "Diana Germetitha" ("Diana" is from Latin while the epithet "Germetitha" is from Thracian) has two different proposed etymologies, "Diana