Plato, Greek philosopher Pyrrho, Greek philosopher Socrates, Greek Philosopher Speusippus, Greek philosopher Sun Bin, Chinese author and military strategist Theophrastus, Greek philosopher Wu Qi, Chinese military strategist and philosopher Xenocrates, Greek philosopher Xenophon, Greek philosopher, writer and historian Zeno of Citium, Greek philosopher Zhuangzi, Chinese philosopher Health professionals Agnodice, female Athenian physician and midwife Inventions, discoveries, introductions Oldest Brahmi script dates from this period. Brāhmī is the ancestor of Brahmic scripts, used in much of India and Southeast Asia. Romans build their first aqueduct. Chinese use the handheld trigger crossbow for the first time. The first crossbow, the gastraphetes, is invented at Syracuse. (pre-421 BC) Burnt brick 'or fired bricks' were first used in Mediterranean civilizations. Donkey-powered mills or 'Pompeiian Mills' were first used in Greece and Italy. In Greece, Aristotle proposes the division of the known sciences. Torque with lion's-head terminals, from Susa (modern Shush, Iran) was made. It is now in Musée du Louvre, Paris. Daric, a coin first minted under Darius I of Persia is made. It is now kept in Heberden Coin Room, Ashmolean Museum, Oxford. Second half of the 4th century BC – Tomb II, so called Tomb of Philip II of Macedon, Vergina, Macedonia is made. Starting in the year 309 BC, the later Chinese historian Sima Qian (145 BC–90 BC) wrote that the Qin-employed engineer Bi Ling of the newly conquered State of Shu in Sichuan had the shoulder of a mountain cut through, making the '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 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. ). First formal system by Pāṇini in Mahajanapada, ancient India and written in Sanskrit. Sovereign states See: List of political entities in the 4th century BC. References External links -6 -96