220 BC

By place

Greece

• Together with fellow Illyrian, Scerdilaidas, Demetrius of Pharos attacks Illyrian cities under Roman protection and leads a piratical squadron into Greek waters. They unsuccessfully attack Pylos, an Achaean town on the Messenian coast, in the Peloponnesus of Greece.
• Scerdilaidas and the Aetolians invade Achaea. With the help of Cynaethan traitors, they attack, seize and burn Cynaetha, a town in the north of Arcadia.
• Rome strikes again against the Illyrian pirates precipitating the Second Illyrian War.
• Demetrius seeks refuge with Philip V of Macedon, who is very resentful of the Roman interference. Rome occupies Demetrius' chief fortresses, Pharos and Dimillos.
• Aratus of Sicyon counters Aetolian aggression by obtaining the assistance of the Hellenic League now under the leadership of Philip V of Macedon. In the resulting Social War, the Hellenic League of Greek states is assembled in Corinth at Philip V's instigation. He then leads the Hellenic League in battles against Aetolia, Sparta and Elis.
• The Gortynians occupy Matala, on the island of Crete.

  Seleucid Empire

• With Molon occupying significant parts of the Seleucid kingdom and assuming the title of king, on the advice of his chief Minister, Hermeias, Antiochus III abandons a campaign to conquer southern Syria from Egypt. Antiochus III instead marches against Molon, defeating and killing him and his brother Alexander on the far bank of the Tigris. Antiochus goes on to conquer Atropatene, the north-western part of Media.
• Meanwhile, the birth of a son to Antiochus III and Laodice leads Hermeias to consider getting rid of the king so that he can rule under the name of the infant son. Antiochus discovers the scheme and arranges the assassination of Hermeias.

  Anatolia

• Antiochus III's commander in Anatolia, Achaeus, having recovered all the districts which Attalus of Pergamum has gained, is accused by Hermeias, the chief minister of Antiochus, of intending to revolt. In self-defence, Achaeus assumes the title of king and rules over the Anatolian parts of the Seleucid kingdom.

  Egypt

• Arsinoe III marries her brother, King Ptolemy IV of Egypt.

  Roman Republic

• During his censorship, the Roman political leader, Gaius Flaminius, builds the Circus Flaminius on the Campus Martius and constructs the Via Flaminia from Rome to Ariminum.

  China

• Qin Shi Huang begins a system of tree-lined roads to interconnect all parts of China, and begins to join regional walls to form the beginnings of the Great Wall.

  By topic

Art

• A bronze statue called Gallic Chieftain killing his wife and himself is made. A Roman copy after the original statue is today preserved at Museo Nazionale Romano in Rome.
• A bronze statue called Dying Gallic trumpeter is made . A marble Roman copy after the original statue is today preserved at Museo Capitolino in Rome.