| Years: 1178 1179 1180 - 1181 - 1182 1183 1184 | |
| Decades: 1150s 1160s 1170s - 1180s - 1190s 1200s 1210s | |
| Centuries: 11th century - 12th century - 13th century | |
| Gregorian calendar | 1181 MCLXXXI |
| Ab urbe condita | 1934 |
| Armenian calendar | 630 ԹՎ ՈԼ |
| Assyrian calendar | 5931 |
| Balinese saka calendar | 1102–1103 |
| Bengali calendar | 587–588 |
| Berber calendar | 2131 |
| English Regnal year | 27 Hen. 2 – 28 Hen. 2 |
| Buddhist calendar | 1725 |
| Burmese calendar | 543 |
| Byzantine calendar | 6689–6690 |
| Chinese calendar | 庚子年 (Metal Rat) 3878 or 3671 — to — 辛丑年 (Metal Ox) 3879 or 3672 |
| Coptic calendar | 897–898 |
| Discordian calendar | 2347 |
| Ethiopian calendar | 1173–1174 |
| Hebrew calendar | 4941–4942 |
| Hindu calendars | |
| - Vikram Samvat | 1237–1238 |
| - Shaka Samvat | 1102–1103 |
| - Kali Yuga | 4281–4282 |
| Holocene calendar | 11181 |
| Igbo calendar | 181–182 |
| Iranian calendar | 559–560 |
| Islamic calendar | 576–577 |
| Japanese calendar | Jishō 5 / Yōwa 1 (養和元年) |
| Javanese calendar | 1088–1089 |
| Julian calendar | 1181 MCLXXXI |
| Korean calendar | 3514 |
| Minguo calendar | 731 before ROC 民前731年 |
| Nanakshahi calendar | −287 |
| Seleucid era | 1492/1493 AG |
| Thai solar calendar | 1723–1724 |
| Tibetan calendar | ལྕགས་ཕོ་བྱི་བ་ལོ་ (male Iron-Rat) 1307 or 926 or 154 — to — ལྕགས་མོ་གླང་ལོ་ (female Iron-Ox) 1308 or 927 or 155 |
Events
- Jayavarman VII assumes control of the Khmer kingdom.
- The word Albigensians first used by chronicler Geoffroy du Breuil of Vigeois to describe the inhabitants of Albi, France.
- September 1 - Pope Lucius III succeeds Pope Alexander III as the 171st pope.
- Chinese and Japanese astronomers observe what has since come to be understood as a supernova. One of only eight supernovae in the Milky Way observed in recorded history, it appeared in the constellation Cassiopeia and was visible in the night sky for about 185 days. The radio source 3C58 is thought to be the remnant from this event.
- Beginning of the Yowa era in Japan. The era is marked by famine.
Births
- Saint Francis of Assisi, Italian founder of the Franciscan Order (died 1226)
- Saint Teresa of Portugal
- Jayavarman VII, king of the Khmer (died 1219)
Deaths
- January 30 - Emperor Takakura of Japan (born 1161)
- March 17 - Henry I of Champagne
- June 30 - Hugh de Kevelioc, 3rd Earl of Chester, English politician (born 1147)
- August 30 - Pope Alexander III
- Taira no Kiyomori, Japanese warlord (born 1118)
- As-Salih Ismail al-Malik, ruler of Syria (born 1163)