The Companions were the elite cavalry of the Macedonian army from the time of King Philip II of Macedon, achieving their greatest prestige under Alexander the Great, and regarded as the first or among the first shock cavalry used in Europe. Chosen Companions, or Hetairoi, formed the elite guard of the king (Somatophylakes).
Alexander Mosaic, showing the Battle of Issus, from the House of the Faun, Pompeii
A heavy cavalryman of Alexander the Great's army, possibly a Thessalian, though the Companion cavalry would have been almost identical (the shape of the cloak of the latter was more rounded). He wears a cuirass (probably a linothorax) and a Boeotian helmet, and is equipped with a scabbarded xiphos straight-bladed sword. Alexander Sarcophagus.
The Companions of Alexander the Great
Historically, cavalry are soldiers or warriors who fight mounted on horseback. Until the 20th century cavalry were the most mobile of the combat arms, operating as light cavalry in the roles of reconnaissance, screening, and skirmishing in many armies, or as heavy cavalry for decisive shock attacks in other armies. An individual soldier in the cavalry is known by a number of designations depending on era and tactics, such as a cavalryman, horseman, trooper, cataphract, knight, drabant, hussar, uhlan, mamluk, cuirassier, lancer, dragoon, or horse archer. The designation of cavalry was not usually given to any military forces that used other animals for mounts, such as camels or elephants. Infantry who moved on horseback, but dismounted to fight on foot, were known in the early 17th to the early 18th century as dragoons, a class of mounted infantry which in most armies later evolved into standard cavalry while retaining their historic designation.
French 4th Hussars at the Battle of Friedland, 1807
Assyrian cavalry
Parthian horseman, now on display at the Palazzo Madama, Turin
Warrior's departure; an Athenian amphora dated 550–540 BC