1091 CE
King William II of England invades western Normandy with a large army. His brothers, Henry and Robert Curthose, mobilize mercenary forces to resist him during a siege at Mont-Saint-Michel. Under terms of the Treaty of Caen, estates on the Cotentin Peninsula of Normandy are surrendered to William, matters being concluded in August. Norman conquest of Sicily: The Normans conquer Noto and complete the 30-year-long conquest of Sicily from the Moorish rulers. Duke Roger Borsa (a son of Robert Guiscard) surrenders his share in the castles of Calabria, and receives his inheritance of Palermo. He grants charters to various towns and encourages urban planning in Apulia and Calabria. London tornado: A T8 tornado (roughly equal to an F4 on the Fujita scale) occurs in London. The wooden London Bridge is demolished and the church of St. Mary-le-Bow is badly damaged.
Conflict & Security
- February 2 – King William II of England invades western Normandy with a large army. His brothers, Henry and Robert Curthose, mobilize mercenary forces to resist him during a siege at Mont-Saint-Michel. Under terms of the Treaty of Caen, estates on the Cotentin Peninsula of Normandy are surrendered to William, matters being concluded in August.source
- February – Norman conquest of Sicily: The Normans conquer Noto and complete the 30-year-long conquest of Sicily from the Moorish rulers. Duke Roger Borsa (a son of Robert Guiscard) surrenders his share in the castles of Calabria, and receives his inheritance of Palermo. He grants charters to various towns and encourages urban planning in Apulia and Calabria.source
- April 29 – Battle of Levounion: Emperor Alexios I, supported by his allies, defeats 80,000 of Pechenegs (including women and children) at the Evros River, near Enos (modern Turkey). The Cumans and Byzantine forces fall upon the enemy camp, slaughtering all in their path. The Pechenegs are butchered so savagely, that this people is almost wiped out.source
- July – King Malcolm III of Scotland invades England, reaching as far south as Durham. The Normans led by William II and Robert march north to oppose the Scots, but a conflict is averted. Malcolm is forced to accept the terms of the Treaty of Abernethy (1072) and pays homage to William.source
- July – The Abbadid dynasty ruling in Al-Andalus (modern Spain) falls when Almoravid forces storm Seville. Confronted with this threat, Emir Muhammad ibn Abu Bakr Muhammad al-Aftas of Badajoz obtains the support of King Alfonso VI ("the Brave") of Castile, in exchange for the Moorish positions on the river Tagus (Sintra, Santarém and Lisbon).source
- Summer – The Norman invasion of Malta: A Norman fleet led by Count Roger I of Sicily ("Bosso") arrives in Malta. Roger disembarks his army, and besieges the island's capital Medina (modern-day Mdina). The inhabitants negotiate peace terms (by promising to pay an annual tribute) and swear an oath of loyalty to Roger. On the way back, the Normans sack the island Gozo.source
- Spring – Tzachas, a Seljuk Turkish military commander, establishes an independent maritime state centred in the Ionian coastal city of Smyrna (modern-day İzmir). He proclaims himself emperor (basileus), and concludes an alliance with the Pechenegs in Thrace. Tzachas uses his fleet to blockade Constantinople by sea, while the Pechenegs besiege the capital by land.source
Religion & Belief
- December – Athanasius VI bar Khamoro becomes (against his will) patriarch and head of the Syriac Orthodox Church in Antioch (until 1129).source
Technology & Infrastructure
- Cardiff Castle in Wales is constructed by Robert Fitzhamon, Norman lord of Gloucester (approximate date).source
Climate & Environment
- October 17 – London tornado: A T8 tornado (roughly equal to an F4 on the Fujita scale) occurs in London. The wooden London Bridge is demolished and the church of St. Mary-le-Bow is badly damaged.source
Births
- September 18 – Andronikos Komnenos, Byzantine prince and generalsource
- December 22 – Jutta von Sponheim, German abbess (d. 1136)source
- Matilda of Rethel, French noblewoman and sovereign (d. 1151)source
- Tiantong Zongjue, Chinese Buddhist monk and patriarch (d. 1162)source
- Hongzhi Zhengjue, Chinese Chan Buddhist monk and writer (d. 1157)source
Deaths
- March 26 – Wallada bint al-Mustakfi, Andalusian female poet (b. 994)source
- June 17 – Dirk V, count of Friesland (west of the Vlie) (b. 1052)source
- June 29 – Frederick of Montbéliard, margrave of Turinsource
- July 5 – William of Hirsau, German abbot and music theoristsource
- August 8 – Altmann of Passau, German bishop and saintsource
- August 25 – Sisnando Davides, Mozarab military leadersource
- December 19 – Adelaide of Susa, margravine of Turinsource
- December 19 – Fujiwara no Tadaie, Japanese statesman (b. 1033)source
- Robert D'Oyly, Norman nobleman (approximate date)source
- Spring – King Stephen II, the last member of the Trpimirović dynasty, dies without leaving an heir after a 2-year reign. War and unrest breaks out in Croatia afterwards. King Ladislaus I of Hungary, on instigation of his sister, Queen Helena, intervenes in the conflict and occupies Croatia. He proclaims himself king, but is contested by the Croatian nobleman Petar Snačić.source
- Wolfhelm of Brauweiler, German Benedictine abbotsource
- Stephen II (or Stjepan), king of Croatia (approximate date)source
- Helena of Hungary, queen consort of Croatia (approximate date)source
- Jordan I (or Giordano), Italo-Norman prince of Capuasource