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 aforementioned inscriptions, Thracian is attested through personal names, toponyms, hydronyms, phytonyms, divine names, etc. and by a small number of words cited in Ancient Greek texts as being specifically Thracian. Other ancient Greek lexical items were not specifically identified as Thracian by the ancient Greeks but are hypothesized by paleolinguists as being or probably being of Thracian origin. Other lexical items are hypothesized on the basis of local anthroponyms, toponyms, hydronyms, oronyms, etc. mentioned in primary sources (see also List of ancient cities in Thrace and Dacia, List of Dacian plant names) . Below is a table showing both words