|Centuries:||2nd century – 3rd century – 4th century|
|Decades:||190s 200s 210s – 220s – 230s 240s 250s|
|Years:||218 219 220 – 221 – 222 223 224|
|221 by topic|
|State leaders – Sovereign states|
|Birth and death categories|
|Births – Deaths|
|Establishment and disestablishment categories|
|Establishments – Disestablishments|
|Ab urbe condita||974|
|Chinese calendar||庚子年 (Metal Rat)
2917 or 2857
— to —
辛丑年 (Metal Ox)
2918 or 2858
|Coptic calendar||−63 – −62|
|- Vikram Samvat||277–278|
|- Shaka Samvat||143–144|
|- Kali Yuga||3322–3323|
|Iranian calendar||401 BP – 400 BP|
|Islamic calendar||413 BH – 412 BH|
|Minguo calendar||1691 before ROC
|Seleucid era||532/533 AG|
|Thai solar calendar||763–764|
Year 221 (CCXXI) was a common year starting on Monday (link will display the full calendar) of the Julian calendar. At the time, it was known as the Year of the Consulship of Gratus and Vitellius (or, less frequently, year 974 Ab urbe condita). The denomination 221 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.
- June 26 – Emperor Elagabalus adopts his cousin Alexander Severus as his heir and receives the title of Caesar.
- July – Elagabalus is forced to divorce Aquilia Severa and marries his third wife Annia Faustina. After five months he returns to Severa and claims that the original divorce is invalid. The marriage is symbolic, because Elagabalus appears to be homosexual or bisexual. According to the historian Cassius Dio, he has a stable relationship with his chariot driver, the slave Hierocles.
- Liu Bei, Chinese warlord and descendant of the royal family of the Han Dynasty, proclaims himself emperor in Sichuan and establish the Kingdom of Shu Han. Three kingdoms arise – the Wei in the north, the Wu in the south and the Shu Han in the west.
- Gongsun Kang, general of Wei
- Lady Zhen (forced to commit suicide by Cao Pi) (b. 183)
- Zhang Fei, general of Shu (assassinated by his subordinates Fan Qiang (范彊) and Zhang Da (張達))