|Millennium:||1st millennium BC|
|Centuries:||4th century BC – 3rd century BC – 2nd century BC|
|Decades:||250s BC 240s BC 230s BC – 220s BC – 210s BC 200s BC 190s BC|
|Years:||225 BC 224 BC 223 BC – 222 BC – 221 BC 220 BC 219 BC|
|222 BC by topic|
|State leaders – Sovereign states|
|Birth and death categories|
|Births – Deaths|
|Establishments and disestablishments categories|
|Establishments – Disestablishments|
|Gregorian calendar||222 BC|
|Ab urbe condita||532|
|Bahá'í calendar||−2065 – −2064|
|English Regnal year||N/A|
|Chinese calendar||戊寅年 (Earth Tiger)
2475 or 2415
— to —
己卯年 (Earth Rabbit)
2476 or 2416
|Coptic calendar||−505 – −504|
|Ethiopian calendar||−229 – −228|
|- Vikram Samvat||−165 – −164|
|- Shaka Samvat||N/A|
|- Kali Yuga||2880–2881|
|Igbo calendar||−1221 – −1220|
|Iranian calendar||843 BP – 842 BP|
|Islamic calendar||869 BH – 868 BH|
|Minguo calendar||2133 before ROC
|Thai solar calendar||322|
|Wikimedia Commons has media related to 222 BC.|
Year 222 BC was a year of the pre-Julian Roman calendar. At the time it was known as the Year of the Consulship of Marcellus and Calvus (or, less frequently, year 532 Ab urbe condita). The denomination 222 BC for this year has been used since the early medieval period, when the Anno Domini calendar era became the prevalent method in Europe for naming years.
- Mediolanum (modern Milan), stronghold of the Gallic tribe of the Insubres (led by Viridomarus), falls to Roman legions in Lombardy (led by consul, Marcus Claudius Marcellus), in the Battle of Clastidium. Marcus Claudius Marcellus personally slays the chief, Viridomarus. This victory removes the Gallic threat to Rome. Marcellus wins the spolia opima ("spoils of honour"; the arms taken by a general who kills an enemy chief in single combat) for the third and last time in Roman history.
- Cleomenes III of Sparta is defeated in the Battle of Sellasia (north of Sparta) by Antigonus III and his allies, the Achaean League and the Illyrians (under the command of Demetrius of Pharos), and flees to Egypt under the protection of King Ptolemy III. Antigonus III's forces occupy Sparta, which is the first time this city has ever been occupied.
- Almost all of Greece falls under Macedonian suzerainty after Antigonus III re-establishes the Hellenic Alliance as a confederacy of leagues, with himself as president.
- The Seleucid forces under their general Achaeus succeed in winning back from Pergamum all the Seleucid domains in Anatolia lost six years earlier.
- Mithridates II of Pontus gives his daughter Laodice in marriage to the Seleucid king Antiochus III. Another of his daughters, also named Laodice, is married about the same time to Achaeus, a cousin of Antiochus.
- The state of Qin conquers the state of Yan and defeats the last defensive forces of the state of Zhao.