At the time of Ervandunis, the Armenian army has indeed been powerful. In the 1st century BC, a Roman author Quintos Curcios Rupos reported that in the famous Battle of Gaugamela in 331 BC, the right wing of the allied forces led by the Persian king Darius III comprised of a 40,000 infantry and 7,000 riders of the Greater Armenia’s army, which showed brilliant skills.
It fought until late night and retreated only when it became clear that the Persians in the center and on the left flank had suffered a crushing defeat.
Rupos did not write anything about the numbers of combating troops of Lesser Armenia on the left flank. Nevertheless, it is obvious that this 47,000 army did not represent all the armed forces of Greater Armenia since Gaugamela was quite far from the borders of Armenia.
At least, the same number of troops had to remain in the country, primarily to ensure the security of the always restless northern and northeastern borders.
In favor of this conclusion, Xenophon’s message also said that only half of the Armenian troops were sent to the Aryan army.
In 9th (or 8th) century BC, the rapidly moving parts (according to modern terminology, the “expeditionary corps”) of the army of King Aram (Arame) also had, according to Movses Khorenatsi, about 50 thousand soldiers.
And again, these 50,000 did not include serf and border garrisons, which did not leave the permanent places of deployment.
Interestingly, the numbers of this corps coincided with the total number of the cavalry of Tigranes the Great, which, according to Plutarch, numbered 55,000 horsemen (including 17,000 armored horsemen).
According to Khorenatsi, in the future, by strengthening the security of the country, Aram added 40,000 soldiers to the infantry and 2,000 to cavalry. The 92,000 combination of these armies marched westward to Caesarea.