Parthians and Saka under ''Erān-Spāhbed'' (suprme commander) Surrena, their Saka commander, defeated the Romans at Carrhae by using their cavalry - horsearchers - hippotaxotoi- and armoured lancers - κατάφρακτος - cataphracts
Plutarch, Greek historian, on Rustam Surena and his warriors -
When they had sufficiently terrified the Romans with their noise, they threw off the covering of their armour, and shone like lightning in their breastplates and helmets of polished Margianian steel, and with their horses covered with brass and steel trappings. [...]. Their first design was with their lances to beat down and force back the first ranks of the Romans, but when they perceived the depth of their battle, and that the soldiers firmly kept their ground, they made a retreat, and pretending to break their order and disperse, they encompassed the Roman square before they were aware of it. Crassus commanded his light-armed soldiers to charge, but they had not gone far before they were received with such a shower of arrows that they were glad to retire amongst the heavy-armed, with whom this was the first occasion of disorder and terror, when they perceived the strength and force of their darts, which pierced their arms, and passed through every kind of covering, hard and soft alike. The Parthians now placing themselves at distances began to shoot from all sides, not aiming at any particular mark (for, indeed, the order of the Romans was so close, that they could not miss if they would), but simply sent their arrows with great force out of strong bent bows, the strokes from which came with extreme violence. The position of the Romans was a very bad one from the first; for if they kept their ranks, they were wounded, and if they tried to charge, they hurt the enemy none the more, and themselves suffered none the less. For the Parthians threw their darts as they fled [so called Parthian shot], an art in which none but the Scythians excel them, and it is, indeed, a cunning practice, for while they thus fight to make their escape, they avoid the dishonour of a flight. ''