Hi I am new to this site and this is my first post.
I believe Plutarch, even though he was before middle ages, described Armenian army of Tigran II time in some great detail. His description is somewhat biased as he tried to depict all the oponents of Roman empire as brutes and barbarians. I don't have any texts or links in front of me right now, but if anyone is interested in this I will try to find some.
I also should have some links to sources about this topic from later period, early middle ages, during the reign of Arshakuni dinasty. I will also try to see if I can find them.
One thing I would like to add, is that it seems the nucleus of Armenian Army in this time was the cavalry which consisted mostly of nobility, naxarar's, sepuh's and azats. It was quite large in proportion to infantry, especially when compared to western armies of Rome and Buzantium. It was called "ayrudzi" which consists of junction of two words words "ayr" (man), "u" (and), "dzi" (horse).
As mentioned before, Armenian cavalry used a special breed of horses. They were bred in Armenian, in regions of Syuniq and Artsax, and they wre well known, valued, and sought after for their strength and stamina.
Armenian cavalry was a sought after prize buy both Persian and Roman rules during their prolonged confrontation in early Middle Ages, both countries always tried to entice Armenian kings and nobles and thus the cavalry to fight on their side.
EDIT Here are some of the sources I was referring to:
The Sparapetut'iwn in Armenia in the Fourth and Fifth Centuries
The Turco-Mongol Invasions and the
Armenian Historical Sources of the 5-15th Centuries
Classical Armenian Literature (some of the same as above)
