Hippeis (Template:Lang-grc) was the Greek term for cavalry. The Hippeus (ἱππεύς) was the second highest of the four Athenian social classes, made of men who could afford to maintain a war horse in the service of the state. The rank may be compared to Roman Equestrians and medieval knights.Among the Athenians, it referred to citizens whose property qualified them for the second class. (See Solonian Constitution)
Among the Spartans, it was the royal guard of honour, consisting of 300 chosen Spartan youth under the age of thirty, who, although originally mounted, afterwards served as heavily-armed foot-soldiers. The cavalry of Athens, which was first formed after the Greco-Persian War, and then consisted of 300 men, from the Periclean period onwards consisted of 1,200 men, including 200 mounted bowmen (hippotoxōtœ), who were slaves belonging to the state, and 1,000 citizens of the two highest classes. They were kept together in time of peace, and carefully drilled; at the great public festivals they took part in the processions. They were commanded by two hipparchi, each of whom had five phylai under him and superintended the levy. Subordinate to these were the ten phylarchi in command of ten phylai. Both sets of officers were drawn from the two highest classes. It was the duty of the boule (council) to see that the cavalry was in good condition, and also to examine new members in respect of their equipment and their eligibility.
The number of horsemen to be dispatched to the field was determined by the decree of the popular assembly. Every citizen-soldier received equipment-money on joining, and during his time of service a subsidy towards keeping a groom and two horses; this grew to be an annual grant from the state, amounting to forty talents, but regular pay was only given in the field.At Sparta it was not until 404 BCE that a regular body of horse was formed, the cavalry being much neglected as compared with the infantry. The rich had only to provide horses, equipment, and armour; for actual cavalry service in time of war, only those unfit for the heavy-armed infantry were drafted off and sent to the field without any preliminary drill. In later times every mora of heavy-armed infantry seems to have had allotted to it a mora of cavalry, of uncertain number. By enlisting mercenaries, and introducing allies into their forces, the Spartans at length obtained better cavalry.
The utility of the Greek citizen-cavalry was small on account of their heavy armour, their metal helmet, and their coat of mail, their kilt fringed with metal flaps, their cuisses reaching to the knee, and their leather leggings. They did not take shields into action. As offensive weapons they had the straight two-edged sword and a spear, used either as a lance or a javelin. Shoeing of horses was unknown to the Greeks, as was the use of stirrups. If anything was used as a saddle, it was either a saddle-cloth or a piece of felt, which was firmly fastened with girths under the horse's belly. The Thessalians were considered the best riders. Trained in horsemanship as well as infantry warfare, the Sacred Band of Thebes  may have been among the volunteer cavalry accompanying the great Theban cavalry commander Pelopidas,  (from whom Philip II of Macedon learned many cavalry skills, to Pelopidas's fatal confrontation with Alexander of Pherae in 364. Cavalry first became important in the Macedonian army under Philip II of Macedon and his son Alexander the Great. Although in earlier times the number of horsemen in the Greek forces was only very small, in the army which Alexander marched into Asia they formed nearly a sixth. The Macedonian cavalry was divided into heavy and light, both consisting of squadrons (ilai) of an average strength of 200 men. Of the heavy cavalry the choicest troops were the Macedonian and Thessalian horsemen, armed in the Greek fashion, who were as formidable in onslaught as in single combat; in order and discipline they far surpassed the dense squadrons of the Asiatic cavalry, and even in attacking the infantry of the enemy they had generally a decisive effect. The light cavalry, which was constituted under the name of prodromoi (skirmishers), consisted of Macedonian sarissophoroi, so called from the sarissa, a lance from 14 to Template:Convert long (Polybius, XVIII, 12), and of Thracian horsemen. The heavy-cavalry men each had a mounted servant and probably a led horse for the transport of baggage and forage. In the time after Alexander there came into existence what were called the Tarentini equites, or light-armed spearmen, with two horses each (192 BCE, Livy, XXXV 28, 29).