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
Ancient Greek verbs three tenses are used, and they distinguish aspect only, not time: The optative mood likewise uses these three tenses, but there is also a future optative, used mainly to report indirectly what would be a future indicative in direct speech. Ancient Greek has no perfect progressive or past perfect progressive. Thus, the meaning "he has been doing" is typically expressed with the present tense, and "he had been doing (earlier)" is expressed with the imperfect tense: For further information on the endings, see Ancient Greek grammar (tables). Dictionaries of Ancient Greek usually give six principal parts for any verb. For