<P> The exception was in Northern Greece, where large flat areas of grassland made cavalry much more practical . Eventually, encounters with Persian cavalry led the Greeks to create their own cavalry arm, the Hippeis, composed mostly of upper - class citizens who could afford to maintain a horse . While cavalry played an increasingly greater part in Greek warfare, its roles were generally restricted to scouting, skirmishing and pursuit . By the end of the Pelopponesian War however, heavy cavalry charges had started to play an increasingly important part in Ancient Greek warfare, with the Battle of Delium showing how their intervention could turn the tide of a battle . The city state of Thebes was particularly famous for its cavalry, with the famed Theban commander Epaminondas using his heavy horse to great effect both at Leuctra as well as Mantineia to rout the Spartan cavalry, and in the process disrupting the legendary Spartan phalanx as well, helping his own to win the day . It's likely that Phillip of Macedon organized his famed Companions after the Theban model, since he spent his youth in the house of Epaminondas as a hostage . </P> <P> The development of the saddle as well as increasingly larger horse breeds led to creation of the Macedonian Companion cavalry, developed during the reign of Philip II of Macedon and later used with great effect by his son, Alexander the Great, in cavalry charges on enemy flanks . In both role and equipment, the Companions was the first cavalry force that was known to represent archetypal heavy cavalry . The Companion cavalry, or Hetairoi, were the elite arm of the Macedonian army, and have been regarded as the best cavalry in the ancient world . </P> <P> In the aftermath of the Macedonian Empire, the Diadochi, successor states created by Alexander the Great's generals, continued the usage of heavy cavalry in their own forces . The Seleucids in particular introduced the use of cataphract into the Western warfare, having learned the practice of completely armouring both man and horse from Iranian tribes encountered during Alexander's anabasis . </P> <P> The stirrup, which gives greater stability to a rider, has been described as one of the most significant inventions in the history of warfare, prior to gunpowder . As a tool allowing expanded use of horses in warfare, the stirrup is often called the third revolutionary step in equipment, after the chariot and the saddle . The basic tactics of mounted warfare were significantly altered by the stirrup . A rider supported by stirrups was less likely to fall off while fighting, and could deliver a blow with a weapon that more fully employed the weight and momentum of horse and rider . Among other advantages, stirrups provided greater balance and support to the rider, which allowed the knight to use a sword more efficiently without falling, especially against infantry adversaries . </P>

Christian armies contained heavily armored cavalry units known as