|909 by topic|
|Ab urbe condita||1662|
|Balinese saka calendar||830–831|
|Chinese calendar||戊辰年 (Earth Dragon)
3605 or 3545
— to —
己巳年 (Earth Snake)
3606 or 3546
|- Vikram Samvat||965–966|
|- Shaka Samvat||830–831|
|- Kali Yuga||4009–4010|
|Japanese calendar||Engi 9
|Minguo calendar||1003 before ROC
|Seleucid era||1220/1221 AG|
|Thai solar calendar||1451–1452|
1035 or 654 or −118
— to —
1036 or 655 or −117
|Wikimedia Commons has media related to 909.|
- King Edward the Elder and his sister, Princess Æthelflæd of Mercia, raid Danish East Anglia and bring back the relics of St. Oswald in triumph. Æthelflæd translates them to the new minister in Gloucester, which is renamed St. Oswald's Priory in his honour.
- Edward the Elder despatches an Anglo-Saxon army to attack the Northumbrian Vikings and ravages Scandinavian York.
- March 18 – The Fatimid Dynasty founded by Shiite Muslims in Ifriqiya (modern Tunisia) gains suzerainty over the Aghlabid Dynasty in North Africa. Emir Ziyadat Allah III escapes to the Near East, unable to secure any help from the Abbasid Caliphate to regain his emirate.
- The Berber Kutama tribesmen under Abdullah al-Mahdi Billah capture the cities of Kairouan and Raqqada. The capital city of the Rustamid imamate, Tihert is destroyed. The remaining Ibadi are forced into the desert.
- Winter – Abdullah al-Mahdi Billah takes up the leadership of the Fatimid state and proclaims himself Caliph Abdullah (al-Mahdi).
- April 27 – The Min Kingdom (modern-day Fujian province) is established by governor Wang Shenzhi (Prince of Langye), with Fuzhou (known as Changle) as its capital. Wang Shenzhi tries to attract scholars who will help to construct an efficient bureaucracy and tax system.
- The last Long Count date is inscribed on a monument at the Mayan site of Toniná (modern-day Chiapas, Mexico), marking the end of the Classic Maya Period.
- Asser, bishop of Sherborne, dies. His See is divided, there are new Bishoprics created at Wells, Crediton, Ramsbury and Sonning.
- Æthelwold, bishop of Winchester (or 904)
- Ar-Radi, Abbasid caliph (d. 940)
- Dunstan, archbishop of Canterbury (d. 988)
- Fujiwara no Morosuke, Japanese statesman (d. 960)
- Shen Lun, Chinese scholar-official (d. 987)
- April 18 – Dionysius II, Syriac Orthodox patriarch of Antioch
- May 9 – Adalgar, archbishop of Bremen
- Aribo of Austria, Frankish margrave
- Asser, bishop of Sherborne (approximate date)
- Cadell ap Rhodri, king of Seisyllwg (Wales)
- Cerball mac Muirecáin, king of Leinster (Ireland)
- Fujiwara no Tokihira, Japanese statesman (b. 871)
- Gerald of Aurillac, Frankish nobleman (b. 855)
- Luo Yin, Chinese statesman and poet (b. 833)
- Muhammad ibn Dawud al-Zahiri, Muslim theologian (b. 868)
- Sochlachan mac Diarmata, king of Uí Maine (Ireland)
- Wighelm, bishop of Chichester
- Wigmund, bishop of Lincoln