The way the Roman and Persian were alike was because of the strong militaries that both of the states had boasted during their respective time period. For example, both of the nations had militaries and government strong enough to sustain a near 720 year war against each other. Lasting from 92 B.C. to 7th century the war did put a major strain on both nations.
Along with the similarities, the soldiers of both nations were life-long trained warriors,