Descriptions by Greek and Roman writers, representations in art and archaeological evidence provide substantial information about the Sasanian army and its weapons. When he founded the Sasanian Empire, Ardashir I (reigned AD 224-240) formed a standing army that was under his personal command. The backbone of the army was the heavy cavalry, which was so effective that the Romans copied it.

Sasanian horsemen were heavily armed with a metal helmet, chain mail of closely fitting plates of iron, a breastplate, gauntlets, a lance, sword, battle-axe, mace, two bows, a quiver with 30 arrows, and a spear. Some also had a lasso, or a sling with slingstones. Coverings of leather protected the horses. The cavalry were supported by armoured war elephants. The infantry consisted of archers who were protected by an oblong curved shield covered with wickerwork and leather, and ordinary footmen. The Sasanians also made use of siege machines for reducing enemy forts and walled towns. Among the surviving Sasanian weapons are impressive double-edged sword blades fitted with elaborate silver or gold hilts and scabbards. The use of steel for sword blades has been recently confirmed by scientific analysis at the British Museum.