3rd century BC
- The first two Punic Wars between Carthage and Rome over dominance in western Mediterranean
- Rome conquers Spain
- Great Wall of China begun
- Indian traders regularly visited Arabia
- Scythians occupy Sogdiana, in modern-day Uzbekistan.
- Mencius, Chinese philosopher and sage (371 - 289 BC).
- Euclid, geometer (c. 365 - 275 BC).
- The Ptolemaic dynasty rules Egypt
- Ptolemy I Soter (305 BC-282 BC) and his wifes Eurydice and Berenice I.
- Ptolemy II Philadelphos (284 BC-246 BC) and his wifes Arsinoe I and Arsinoe II Philadelphos.
- Ptolemy III Euergetes I (246 BC-222 BC) and his wife Berenice II.
- Ptolemy IV Philopater (222 BC-204 BC) and his wife Arsinoe III.
- Ptolemy V Epiphanes (204 BC-180 BC) and his wife Cleopatra I.
- Archimedes of Syracuse, mathematician, physicist, and engineer (c. 287 - 212 BC).
- Apollonius of Perga, mathematician (c. 262 - 190 BC).
- Qin Shi Huang Di, Chinese Emperor (259 - 210 BC, reigned 246 - 210 BC).
- Hannibal, military leader of Carthage (247 - 182 BC).
Inventions, discoveries, introductions
Decades and yearsca:Segle III AC
[[da:3. �rhundrede f.Kr.]] de:3. Jahrhundert v. Chr. es:Siglo III adC eo:3-a jarcento a.K. [[fr:IIIe si�cle av. J.-C.]] it:III secolo AC lb:3. Joerhonnert v. Chr. nl:3e eeuw v. Chr. ja:紀元前3世紀 pl:III wiek p.n.e. ru:III век до н. э. sl:3. stoletje pr. n. št. sv:200-talet f.Kr. uk:3 століття до Р.Х. zh:前3世纪