Sassanid cataphracts were the elite heavy cavalry of the Persian Empire, descended from an older Iranian tradition developed under the Parthians. They were essentially the ancient world's tanks, with both warrior and warhorse protected by extensive chainmail, scale and lamellar armor. Armed with long cavalry lances, swords and shields, they were designed to absorb missile fire and smash through enemy formations with the immense momentum of an armored horse and rider. The Sassanids refined this tradition into a highly prestigious military institution associated with the aristocratic aswaran, making heavily armored cavalry one of the defining strengths of the Sassanid army.

Their influence extended far beyond Persia. Rome encountered Iranian cataphracts repeatedly during its wars with the Parthians and Sassanids and eventually developed its own heavily armored cavalry, while the Byzantine Empire continued and refined the tradition for centuries. Although European knights did not simply descend directly from Sassanid cataphracts, the Iranian model formed part of a much larger evolution of armored horse warfare that passed through Rome and Byzantium and influenced later medieval military traditions. In this sense, Sassanid cataphracts stand among the important ancestors of the heavily armored knights who would dominate medieval battlefields.