209 BC

By place

Roman Republic

• The Romans under Quintus Fabius Maximus Verrucosus capture Tarentum, which the Carthaginian general Hannibal has held for three years.
• The Battle of Canusium is fought between Hannibal's Carthaginian army and a Roman force led by Marcus Claudius Marcellus. The battle is indecisive.
• From his headquarters at Tarraco, Publius Cornelius Scipio, the Roman commander in Spain, launches a combined military and naval assault on the Carthaginian headquarters at Carthago Nova. He successfully besieges and captures the city. In capturing this city, Scipio gains access to copious stores and supplies, Spanish hostages, the local silver mines, a splendid harbour and a base for an advance farther south.

  Seleucid Empire

• The King of the Parthians, Arsaces II, is attacked by the Seleucid king Antiochus III, who takes Hecatompylos, the Arsacid capital and Syrinx in Hyrcania. Antiochus III defeats Arsaces II at the Battle of Mount Labus and then forces Arsaces II to enter into an alliance with the Seleucids.

  Greece

• As strategos of the Achaeans, the Greek general Philopoemen is responsible for turning the Achaean League into an aggressive military power. He builds up the League's military capability. The Achaean League's army and cavalry under Philopoemen then defeat the Aetolians on the Elean frontier.

  China

• Jiao, Lord of Wey is deposed by Emperor Qin Er Shi, marking the end of the state of Wei
• In August, Chen Sheng and Wu Guang blow an uprising to oppose Qin

  Central Asia

• Modun khaan inherits Teoman's Hunnu confederations and founds the Xiongnu Empire. Modu's forces push into Northern China, threatening the Qin Empire and forcing them to further fortify the Great Wall.