Editing Hellenistic period (section)

=== Military science ===
{{Further|Hellenistic armies}}
[[File:Ancient Mechanical Artillery. Pic 01.jpg|thumb|upright=0.9|Ancient mechanical artillery: Catapults (standing), the chain drive of [[Polybolos]] (bottom center), [[Gastraphetes]] (on wall)]]
Hellenistic warfare was a continuation of the military developments of [[Iphicrates]] and [[Philip&nbsp;II of Macedon]], particularly his use of the [[Macedonian phalanx]], a dense formation of [[phalangite|pikemen]], in conjunction with heavy [[companion cavalry]]. Armies of the Hellenistic period differed from those of the classical period in being largely made up of professional soldiers and also in their greater specialization and technical proficiency in [[siege warfare]]. Hellenistic armies were significantly larger than those of classical Greece relying increasingly on Greek [[mercenaries]] (''misthophoroi''; men-for-pay) and also on non-Greek soldiery such as Thracians, Galatians, Egyptians and Iranians. Some ethnic groups were known for their martial skill in a particular mode of combat and were highly sought after, including [[Hellenistic armies#Tarantine cavalry|Tarantine cavalry]], Cretan archers, Rhodian slingers and Thracian [[peltasts]]. This period also saw the adoption of new weapons and troop types such as [[Thureophoroi]] and the [[Thorakitai]] who used the oval [[Thureos]] shield and fought with javelins and the [[machaira]] sword. The use of heavily armored [[cataphracts]] and also [[horse archers]] was adopted by the Seleucids, Greco-Bactrians, Armenians and [[Kingdom of Pontus|Pontus]]. The use of [[war elephants]] also became common. Seleucus received Indian war elephants from the [[Mauryan empire]], and used them to good effect at the [[battle of Ipsus]]. He kept a core of 500 of them at [[Apamea (Euphrates)|Apameia]]. The Ptolemies used the smaller African elephant.

Hellenistic military equipment was generally characterized by an increase in size. [[Hellenistic-era warships]] grew from the [[trireme]] to include more banks of oars and larger numbers of rowers and soldiers as in the Quadrireme and Quinquereme. The Ptolemaic [[Tessarakonteres]] was the largest ship constructed in Antiquity. New siege engines were developed during this period. An unknown engineer developed the torsion-spring catapult ({{circa|360&nbsp;BC}}) and Dionysios of Alexandria designed a repeating [[ballista]], the [[Polybolos]]. Preserved examples of ball projectiles range from {{cvt|4.4|to|78|kg|lb}}.<ref>Bugh, p. 285.</ref> [[Demetrius Poliorcetes]] was notorious for the large [[siege engines]] employed in his campaigns, especially during the 12-month siege of Rhodes when he had Epimachos of Athens build a massive 160 ton siege tower named [[Helepolis]], filled with artillery.