- Gregorian calendar
- 800 BC, DCCC BC
- Ancient egypt era
- XXIII dynasty , 81
- Ancient greek olympiad summer
- 24 before 1st Olympiad
- Balinese saka calendar
- N/A
- Bengali calendar
- −1393 – −1392
- Buddhist calendar
- −255
- Burmese calendar
- −1437
- Byzantine calendar
- 4709–4710
- Chinese calendar
- 庚子 年 (Metal Rat ), 1898 or 1691, — to — , 辛丑年 (Metal Ox ), 1899 or 1692
- Coptic calendar
- −1083 – −1082
- Ethiopian calendar
- −807 – −806
- Hebrew calendar
- 2961–2962