A hypaspist ( "shield bearer" or "shield covered") is a squire, man at arms, or "shield carrier". In Homer, Deiphobos advances "" () or under cover of his shield. By the time of Herodotus (426 BC), the word had come to mean a high status soldier as is strongly suggested by Herodotus in one of the earliest known uses: A similar usage occurs in Euripides's play Rhesus and another in his Phoenissae. Xenophon was deserted by his horse in a particularly sticky situation. A hypaspist would differ from a skeuophoros in most cases because the "shield bearer" is a free warrior and the "baggage carrier" was probably usually a slave. The word may have had Homeric and heroic connotations that led Philip II of Macedon to use it for an elite military unit. This unit, known as the Hypaspistai, or hypaspists, was probably armed in the hoplite manner, with a large concave shield (Aspis) and a spear (Dory), in addition to spolas or linothorax body-armor, hoplite's helmet, greaves and a xiphos or kopis sword (though their equipment was likely more ornate than main-line soldiers).. In contrast, the main Macedonian Phalanx consisted of the pikemen known as phalangites. These men were armed with the Sarissa, a pike of between 4 to 6.7m, a small flat shield and a shortsword called a Xiphos as a secondary weapon. The divergence in equipment and tactics between the traditional Greek Hoplite phalanx and the Macedonian Phalanx is attributed to Philip II of Macedon, the father of Alexander the Great. In set piece battles, the Macedonian Hypaspists were positioned on the flanks of the phalangite's phalanx; in turn, their own flanks were protected by light infantry and cavalry. Their job was to guard the flanks of the large and unwieldy pike phalanx. The armored Phalangites with their sarissas were not particularly agile or able to turn quickly, so hypaspists would prevent attacks on the vulnerable sides of the formation. Their role was vital to the success of Philip's tactics because the Macedonian phalanx was all but invulnerable from the front, and was, with five layers of iron spikes moving in unison, used as the anvil in a hammer and anvil tactic, where the Companion cavalry was the hammer that smashed the enemy against an anvil of thousands of iron spikes. As such an important yet vulnerable part of the Macedonian army, it needed protection for its