The scythed chariot was a modified war chariot invented by the Persian emperor Cyrus by at least 401 BC. A scythed chariot was simply a war chariot with a blade mounted on both ends of the axle. The blades extended horizontally for a meter on the sides of the chariot, rotating as the chariot was pulled.
The scythed chariot was pulled by a team of four horses and manned by a crew of up to three men, one driver and two warriors. Theoretically the scythed chariot would plow through infantry lines, cutting combatants in half or at least opening gaps in the line which could be exploited. In practice there were several problems. It was difficult to get horses to charge into the tight phalanx formation of the Greek/Macedonian hoplites (infantry). Also, a disciplined army could diverge as the chariot approached, and then collapse quickly behind it, allowing the chariot to pass without causing many casualties. Third, war chariots had limited military capabilities. They were strictly an offensive weapon and were best suited against infantry in open engagements where the charioteers had room to maneuver.
Despite these shortcomings scythed chariots were used with some success by the Persians, the kingdoms of the Hellenistic Era, and later Rome.
Late in the Imperial period the Romans experimented with an unusual variant of the idea that called for cataphract-style lancers to sit one or more of the horses drawing the chariot, to increase the shock of the charge. (The unit was short-lived, suggesting that the idea was not effective.)
