希腊化时代的陆军

The Antigonid kingdom of Macedon's cavalry only constituted a small fraction of the army. Duncan Head estimates this fraction as between 5 and 10% of the total strength of the Antigonid armies. This may well be due to over-campaigning, high casualties or even because many of the Macedonian noblemen who formed much of the heavy cavalry of Philip II and Alexander went east and never came back. But, by the time of Philip V and Perseus, cavalry strength had slowly increased. Philip V had a cavalry force of 400 'Household' cavalry, called the Royal or Sacred Ile in a campaign in 219 BC. This small number of native horse was then supplemented by mercenary cavalry.

In Ptolemaic Egypt, the cavalry forces were led by a hipparchos, who commanded a hipparchia. The hipparchiai were divided into ilai, then into lochoi and then into dekades (sing. dekas, a file of 10 men). Hipparchiai fall into two categories. There were five known hipparchiai in the 3rd century, of which the 4th and 5th are known to have been in existence in the 2nd century BC. Other than these, there were four hipparchiai of lower status known by 'ethnic' names; the Thessalians, Thracians, Mysians and Persians. These probably were not actual cavalry troops from those ethnic groups, but more like the Tarantine cavalry mercenaries who did not need to be from Taras to be called thus.

The Seleucid empire's cavalry were placed in units of oulamoi and then into divisions of ilai. Other than the usual auxiliary, citizen and militia cavalry units, the main elite cavalry units of the Seleucids were the Agema and the Hetairoi ("Companions"). The Hetairoi were the standing elite cavalry unit of the Seleucid army, serving both in peace and war. The Agema was recruited from the Medes and their neighbours, although after the Parthian conquest of Media they were probably recruited from Macedonian settlers. The Hetairoi would escort the king into battle or both the Hetairoi and Agema would escort the king under direct command. Amongst these units were the various grades of 'Kings Friends' or Basilikoi Philoi, who made up other elite cavalry units similar to the Companions.

Hellenistic cavalry is much more diverse than the Greek cavalry of earlier eras. Greek tactical manuals categorize them as cataphracts (fully armored, a type of cavalry not to be confused with the Seleucid, Parthian or Byzantine cataphracts) and aphracts (unarmored). Cataphracts was a term commonly employed to describe fully armored cavalry of various weights, with or without shield (usually a thureos), usually armed with a lance. Unarmored cavalry was classified as lancers, javelineers and bowmen. Lancers (xystophoroi or doratophoroi) charged the enemy in dense formations. Javelineers were also called Tarentines and attacked the enemy from afar. Afterwards, they would charge the enemy with lances or keep their distance, in which case they were called light cavalry and/or Tarentines proper. A further category of light cavalry was that of the mounted bowmen, which were collectively called Scythians. These are broad categories, as attested by both Aelian and Asclepiodotus. Arrian's categorization is also very similar.

Most cavalry units of the Hellenistic era were moderately armored and would be armed with javelins or/and lances. Cataphracts were introduced to the Hellenistic world by the Seleucids in the late 3rd century BC and are attested to have been used, probably in a lighter version and for a very limited time, also by the kingdom of Pergamon. Antiochus III was able to field an extraordinary 6,000 men at Magnesia, the first testimony of cavalry gaining victory over the closed ordered ranks of a competent infantry, yet to no avail. The Seleucids also had moderate access to horse archers from their eastern borders, although they never fielded them in large numbers. The Ptolemies also deployed heavy armored lancers, never cataphracts, probably because of the high temperatures prevalent in their empire. In Macedonia, armored lancers were also deployed, after the tradition of Alexander's Hetairoi, yet their capability could not compare to that of their predecessors. In the rest of the Greek world, cavalry maintained its traditional equipment of javelin and short lance. Apart from the cavalry types used by the Greeks, the Hellenistic kingdoms also used cavalry from subordinate and allied barbarian states, which varied in quality, armor and equipment. Mercenary cavalry troops were also employed, including Thracians, Armenians, and even Berbers.

No cavalry formation is unfortunately mentioned in the existent descriptions of cavalry battles, but all ancient Greek tactical manuals, including Asclepiodotus' Techne Taktike written in the 1st century BC, clearly and in detail describe the wedge and the rhombus formations, stating that they were in use at least at the time of their compilation as well as the more common square and rectangular formations. Thus, we have to accept the probability that they were used throughout the Hellenistic era. Other formations attested and probably used were the Tarantenic circle, employed by the Tarentines proper and the Scythian formation, attested in use by the Scythian horse archers. Both were skirmishing formations and facilitated continuous harassment while at the same time providing the required mobility to avoid enemy charges.

Although, throughout the Hellenistic era, more importance was usually given to the role of the infantry than to cavalry, most major battles of the era were gained because of good or bad cavalry performance. Antigonus was defeated at Ipsus, because his victorious cavalry failed to return from the pursuit before the 400 enemy elephants effectively blocked its way back. Antiochus was defeated at Raphia, when, engaging in pursue of the defeated enemy cavalry, he failed to return and charge the enemy phalanx. At the Battle of Cynoscephalae, the Aetolian cavalry played a key role in the battle and at Pydna, the Macedonian lancers suddenly left the battlefield allowing the Romans to surround and massacre Perseus' phalanx. At Magnesia, the cataphracts routed the Roman legions but it was Eumenes' cavalry that turned the tide and effectively ensured victory for the Romans. In Sellasia, it was Philopoemen's cavalry that conquered Oida, earning the admiration of Antigonus Doson.

A modern conception, there is no mentioning of a "heavy cavalry" in the Greek military manuals. Unfortunately, even today, we don't have a concrete notion of what "heavy cavalry" should be. According to one school of thought, it is any cavalry capable of shock action against the enemy line, according to another, it should just be heavily armored. According to the Greeks, we have to define it as any cavalry that was not considered "light", that is, which was not purely skirmishing. Another aspect of the cavalry of the ancient era we have to keep in mind is the unwillingness to use even the best trained and heaviest of cavalries against any dense mass of able infantry. This is evident in many ancient descriptions of battles. According to Arrian, when Alexander faced the Indian tribe of the Malli, he did not dare assault them with his, by now, veteran Heteroi or Thessalians, but he followed the customary cavalry tactics of attacks and retreats (perispasmoi).

Thus, most cavalry types of the Hellenistic armies can be considered heavy, regardless of their armor, as long as they are equipped with lances and act in dense formations. Traditional Greek cavalry was usually employed to cover a retreat or pursue a retreating enemy. A cavalry engagement usually involved a lengthy exchange of javelins; close combat was avoided. The Macedonian Hetairoi (Companions; Companion Cavalry) may have been the first true, able shock cavalry, armed with long lances and heavy armor. Their tradition was carried on in the Hellenistic times and troops similarly armed were called doratophoroi or xystophoroi (both terms translated as lance bearers or plainly lancers). The term Hetairoi was reserved for units comprising men of aristocratic blood. These doratophoroi were primarily used against enemy cavalry; their use against densely deployed infantry was very limited. Their extreme version were the cataphracts of the Seleucid cavalry. The various Agemata (pl. of Agema), usually the elite bodyguards of the Hellenistic Kings, were similarly armed.

Cataphracts were heavily armed and armoured cavalrymen. The Cataphract (Kataphraktoi) were first introduced into the Hellenistic military tradition with the Seleucid Antiochus III the Great's anabasis in the east from 212-205 BC. With his campaigns in Parthia and Bactria, he came into contact with Cataphracts and copied them. Most of the Seleucid heavy cavalry after this period were armed in this manner, despite keeping their original unit names. The Cataphract generally only served in the eastern Hellenistic armies.

Both man and horse were entirely encased in armour—in the form of scale or banded segments sewn onto a fabric. Riders' faces were covered in seamless metal helmets. The weight carried by the horse was excessive, and prolonged charges were out of the question. Instead, cataphracts trotted to within a reasonable distance before charging, exerting energy only during the decisive engagement. Once in combat, the cataphract and his steed enjoyed superb protection from attacks thanks to their armour. However, stamina, endurance and heat were always concerns in extended combat.

The standard cataphract weapon was a xyston-like spear. For close-quarter combat, a mace or sword was made available as a secondary weapon. The mace and cataphract ideas were combined into the Sassanid-introduced and Roman-named Clibanarii, who were armoured, both man and beast, in chainmail, and armed with a mace.

Originally the cavalry of the army of the Greek city of Tarantas (Tarentum) in Magna Graecia, it was renowned for its peculiar battle tactics. It was the only cavalry of the Graeco-Roman world to employ pure, advanced skirmishing tactics. It was unarmored and normally equipped with a shield and javelins, which it hurled at the enemy, evading any attempt to engage in close combat. In the Hellenistic era, we have numerous references to Tarantine units, even in the armies of the eastern Macedonian empires, but unfortunately no definite account of their equipment or their tactical use. From the Greek tactical manuals we learn that Tarantines is the collective name of the lightly armored cavalry, which was equipped with javelins and lance, that first skirmishes with the enemy and then charges. Cavalry that avoided using the charge, preferring to remain at a distance and skirmish, was called Tarantines proper. From these texts, we can safely deduce that, during Hellenistic times, the term "Tarantines" no longer bore a geographical significance[9][10] and was used purely as a tactical term.

War elephants were considered untrustworthy by Greek military writers, but played an important role in many battles of the Hellenistic era, especially in the east. As was proven many times before, as well as in the wars of Pyrrhus of Epirus and Hannibal, elephants could throw a competent enemy battle line into confusion and win the day, as long as the enemy was not accustomed to battle against them. Yet, if used for a frontal assault, the danger of them being routed and falling in panic into the lines of their own army was great. As Livy attested, elephants were more dangerous when scared than when controlled.[13] The Hellenistic generals were well aware of this fact and thus did not deploy them before or among their battle line, as was the case in Hydaspes or in Zama, both examples of how routing elephants could cost the battle. Instead, they were deployed on the wings, where they could keep the enemy cavalry at bay, protecting the infantry from a cavalry outflank. Against them, the enemy would use his own elephants, a necessity, since cavalry would never be able to conquer them. There, should they be defeated, they would have space to retreat without getting in the way of the infantry. Elephants would sometimes be accompanied by irregular infantry battalions, which would assist in the elephantomachia (elephant battle), while at the same time protecting their side from enemy infantry.

A peculiar use of the elephants is attested during the battle of Ipsus, where Seleucus Nicator posted his elephants in a long line between the battlefield and the victorious cavalry of Demetrius, effectively keeping him away and gaining victory. This incident might be the best attestation to the unwillingness of horses to approach an elephant.

War elephants were typically fitted with a tower on their back that housed several soldiers armed with sarissae and projectiles (arrows or javelins) to unload on the enemy. The rider (mahout) sat across the neck and guided the elephant into battle. Armour too, was sometimes wrapped around the elephants to protect them and increase the natural defense offered by the thickness of their hides. The size of the tower would be proportionate to the size of the elephants, the Asiatic being considerably larger than the North African elephants used by the Ptolemies. Polybius gives a valuable account of an elephant battle between these two species in his description of the battle of Raphia, where the beasts of Antiochus easily routed their African counterparts, yet the King failed to claim victory, since Ptolemy's phalanx forced his center to retreat in disorder.[14]

Artillery was also used in the Hellenistic era, albeit rarely and without much effect. Catapults and other heavy artillery had a short range, which meant they would have to be up close to the enemy to make an impact. However, this made them vulnerable, indeed 'the difficulty of getting catapults quickly into, and out of, action might make them more of a liability than an asset in fluid warfare'.[15] Machanidas of Sparta learnt this the hard way when his artillery at the battle of Mantinea in 207 BC was quickly taken by Philopoemen's Achaean infantry.[16] Philip V of Macedon used artillery, in conjunction with defensive field works, in his defence of the Aous Valley in the Second Macedonian War, causing high Roman casualties.[17] Antiochus the Great is attested to have used it at Thermopylae, resting it in imposing positions over the prospected battlefield. Perseus of Macedon used artillery in the Third Macedonian War to defend the Elpeus river from Aemilius Paulus, who did indeed move away to seek another route around this defensive line. It was also used in fortified towns to harass enemy assailants. Its use in the battlefield does not seem to have been important, as mass use is not attested until much later, as Arrian clearly suggests in his "Array against the Alans".