The Sasanian army was the primary military body of the Sasanian armed forces, serving alongside the Sasanian navy. The birth of the army dates back to the rise of Ardashir I (r. 224–241), the founder of the Sasanian Empire, to the throne. Ardashir aimed at the revival of the Persian Empire, and to further this aim, he reformed the military by forming a standing army which was under his personal command and whose officers were separate from satraps, local princes and nobility. He restored the Achaemenid military organizations, retained the Parthian cavalry model, and employed new types of armour and siege warfare techniques. This was the beginning for a military system which served him and his successors for over 400 years, during which the Sasanian Empire was, along with the Roman Empire and later the Eastern Roman Empire, one of the two superpowers of Late Antiquity in Western Eurasia. During the reign of Khosrow the Sasanian army underwent major reforms. The Sasanian army protected Eranshahr ("the realm of Iran") from the East against the incursions of central Asiatic nomads like the Hephthalites and Turks, while in the west it was engaged in a recurrent struggle against the Roman Empire.
Sassanid army in the context of Horse archer
Mounted archery is a form of archery that involves shooting arrows while on horseback. A horse archer is a person who does mounted archery. Archery has occasionally been used from the backs of other riding animals. In large open areas, mounted archery was a highly successful technique for hunting, for protecting herds, and for war. It was a defining characteristic of the Eurasian nomads during antiquity and the medieval period, as well as the Iranian peoples such as the Alans, Sarmatians, Cimmerians, Scythians, Massagetae, Parthians, and Persians in Antiquity, and by the Hungarians, Mongols, Chinese, and Turkic peoples during the Middle Ages. The expansion of these cultures have had a great influence on other geographical regions including Eastern Europe, West Asia, and East Asia. In East Asia, horse archery came to be particularly honored in the samurai tradition of Japan, where horse archery is called Yabusame.
The term mounted archer occurs in medieval English sources to describe a soldier who rode to battle but who dismounted to shoot, similar to the later firearm-equipped dragoons. Horse archer is the term used more specifically to describe a warrior who shoots from the saddle at the gallop. Another term, "horseback archery", has crept into modern use.
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