Editing 4th century BC (section)

==Inventions, discoveries, introductions==
{{see also|Timeline of historic inventions#4th century BC}}
[[Image:ChineseCrossbow.JPG|thumb|right|200px|A [[Han dynasty]] Chinese [[crossbow]] from the 2nd century BCE.]]
* Oldest [[Brahmi script]] dates from this period. Brāhmī is the ancestor of [[Brahmic scripts]], used in much of [[India]] and [[Southeast Asia]].
* [[Ancient Rome|Romans]] build their first [[aqueduct (Roman)|aqueduct]].
* [[History of China|Chinese]] use the handheld trigger [[crossbow]] for the first time.
* The first crossbow, the [[gastraphetes]], is invented at [[Syracuse, Sicily|Syracuse]]. (pre-421 BCE)
* Donkey-powered mills or 'Pompeiian Mills' were first used in Greece and Italy.<ref>{{cite web |last1=Watts |first1=Sue |title=Pompeiian Mill (Animal Powered) |url=https://catalogue.millsarchive.org/animal-powered-mills-in-a-bakery-in-pompeii |website=Mills Archive Catalogue |publisher=The Mills Archive Trust |access-date=24 February 2019}}</ref>
* In Greece, Aristotle proposes the division of the known sciences.
* [[Torc|Torque]] with lion's-head terminals, from [[Susa]] (modern [[Shush, Iran]]) was made. It is now in [[Musée du Louvre]], Paris.
* [[Persian daric|Daric]], a [[coin]] first minted under [[Darius I]] of [[Persia]] is made. It is now kept in [[Charles Buller Heberden|Heberden]] Coin Room, [[Ashmolean Museum]], [[Oxford]].
* Second half of the 4th century BCE – Tomb II, so called Tomb of [[Philip II of Macedon]], [[Vergina]], [[Macedonia (ancient kingdom)|Macedonia]] is made.
* Starting in the year [[309 BCE]], the later Chinese historian [[Sima Qian]] (145 BCE–90 BCE) wrote that the Qin-employed engineer Bi Ling of the newly conquered [[Shu (state)|State of Shu]] in [[Sichuan]] had the shoulder of a mountain cut through, making the [[Dujiangyan|'Separated Hill']] that abated the Mo River, and excavated two canals in the plain of [[Chengdu]]. The significance of this was phenomenal, as it allowed the new Guardian [[irrigation]] system to populate an area of some 40 by 50 miles (60 × 80&nbsp;km) with over five million people, still in use today (Needham, ''Science and Civilization in China'', Volume 4, Part 3, 288).
* The Chinese astronomer [[Gan De]] divides the [[celestial sphere]] into 365¼ degrees, and the tropical year into 365¼ days at a time when most astronomers used the [[Babylon]] division of the celestial sphere as 360 degrees (Deng, Yinke. [2005] (2005). ''Chinese Ancient Inventions''. {{ISBN|7-5085-0837-8}}).
* First [[formal system]] by [[Pāṇini]] in [[Mahajanapada]], [[History of India|ancient India]] and written in [[Sanskrit]].