Year 927 (CMXXVII) was a common year starting on Monday (link 'will display the full calendar) of the Julian calendar.
- May 27 – Simeon I, emperor (tsar) of the Bulgarian Empire, dies of heart failure in his palace at Preslav after a 34-year reign. He is survived by four sons and succeeded by his second son Peter I, who signs a peace treaty with the Byzantine Empire. The peace is confirmed by Peter's marrying Maria Lekapene (the daughter of Christopher Lekapenos, son and co-emperor of Romanos I). The treaty restores the borders to those established by several treaties (thus recognizing Bulgaria's possession of Macedonia).
- July 12 – King Æthelstan of Wessex claims his kingdom and receives the submission of High-Reeve Ealdred I of Bamburgh and probably also of Owain ap Dyfnwal, King of Strathclyde, at Eamont Bridge. He unifies the various small kingdoms of the Anglo-Saxon Heptarchy, creating the Kingdom of England, and also secures a pledge from King Constantine II of Scotland, that he will not ally with the Viking kings. This summer also Kings Hywel Dda of Deheubarth and Owain of Glywysing and Gwent submit to the overlordship of Æthelstan at Hereford. The borders between England and Wales are set at the River Wye.
- Summer – The Hungarians fight in Rome, helping Margrave Peter against Pope John X. They then go to southern Italy, and conquer the cities of Taranto and Oria.
- August 15 – The Saracens led by the Slavic Sabir, in conjunction with the Fatimids from Sicily, capture and destroy Taranto. They enslave much of the population.
- January 13 – Berno of Cluny, Frankish monk and abbot
- January 14 – Wang Yanhan, king of Min (Ten Kingdoms)
- May 27 – Simeon I, emperor (tsar) of the Bulgarian Empire
- August 24
- September 14 – Cele Dabhaill mac Scannal, Irish abbot
- November 7 – Zhu Shouyin, general of Later Tang
- November 20 – Xu Wen, general and regent of Wu (b. 862)
- Abdallah ibn Muhammad, Abbasid vizier (or 926)
- Gyeongae, king (55th ruler) of Silla (Korea)
- Ha-Mim, Moroccan prophet and messenger of Islam
- Ibn al-Dahhak, Kurdish chieftain (approximate date)
- Miró II, count of Cerdanya and Besalú (Spain)
- Ren Huan, general and chancellor of Later Tang
- Shin Sung-gyeom, Korean general (Three Kingdoms)
- Sigtrygg Cáech, Viking king of Scandinavian York
- Zhang Ge, politician and chancellor of Former Shu
- ^ John V.A. Fine, Jr (1991). The Early Medieval Balkans: A Critical Survey from the Sixth to the Late Twelfth Century, p. 161. ISBN 978-0-472-08149-3.
- ^ Palmer, Alan; Palmer, Veronica (1992). The Chronology of British History. London: Century Ltd. pp. 42–47. ISBN 978-0-7126-5616-0.