1000 CE

In the proleptic Gregorian calendar, it was a non-leap century year starting on Wednesday (like 1800).

Geopolitics & Diplomacy

In Great Britain, a unified Kingdom of England had developed out of the various Anglo-Saxon kingdoms.source
Sancho III of Pamplona became King of Aragon and Navarre. The Reconquista was gaining some ground, but the southern Iberian peninsula would still be dominated by Islam for centuries to come; Córdoba was the world's largest city at this time, with 450,000 inhabitants.source

In the Kingdom of Croatia the army of the Republic of Venice led by Doge Pietro II Orseolo conquered the island of Lastovo.source
The Byzantine Empire under the Macedonian dynasty was engaged in a long and hard war with the First Bulgarian Empire. The Byzantine generals, Theodorokanos and Nikephoros Xiphias captured the former Bulgarian capitals of Pliska and Great Preslav, along with Little Preslav, extending Byzantine control over the northeastern portion of the Bulgarian state (Mysia and Scythia Minor). At the same time, Byzantium was instrumental in the Christianization of Kievan Rus' and of other medieval confederations of Slavic states.source
In Scandinavia, Christianization was in its early stages, with the Althing of the Icelandic Commonwealth embracing Christianity in the year 1000. On September 9, the King of Norway, Olaf Tryggvason, was defeated by the Scandinavian kingdoms of Denmark and Sweden in the Battle of Svolder. Sweyn Forkbeard established Danish control over part of Norway. The city of Oslo was founded in Norway (the exact year is debatable, but the 1,000 year anniversary was held in the year 2000). It is known that in or around this year, Norse explorer Leif Erikson became the first European to land in the Americas, at L'Anse aux Meadows in modern-day Newfoundland.source

Ichimonjiya Wasuke, the oldest surviving wagashi store, is established as a teahouse adjacent to Imamiya Shrine.source
The Bell foundry was founded in Italy by Pontificia Fonderia Marinelli.source
The papacy during this time was in a period of decline, in retrospect known as the saeculum obscurum ("Dark Age") or "pornocracy" ("rule of harlots"), a state of affairs that would result in the Great Schism between Roman Catholicism and Eastern Orthodoxy later in the 11th century.source
In continental Europe, the Holy Roman Empire established itself as the most powerful state. The Holy Roman Emperor Otto III made a pilgrimage from Rome to Aachen and Gniezno (Gnesen), stopping at Regensburg, Meissen, Magdeburg, and Gniezno. The Congress of Gniezno (with Bolesław I the Brave) was part of his pilgrimage. In Rome, he built the basilica of San Bartolomeo all'Isola, to host the relics of St. Bartholomew.source
The archdiocese in Gniezno was founded; the first archbishop was Radim Gaudentius, from Slavník dynasty, and dioceses in Kołobrzeg, Kraków and Wrocław.source

April 8: Fujiwara no Shoshi is promoted to Empress (Chugu), while there is another empress, Fujiwara no Teishi (kogo) - this is the first time that there are two empressessource
The Kingdom of Hungary was established in 1000 as a Christian state. In the next centuries, the Kingdom of Hungary became the pre-eminent cultural power in the Central European region. On December 25, Stephen I was crowned as the first King of Hungary in Esztergom.source
Palace Scandal: Princess Consort Yasuko has an affair. Michinaga (her half-brother) investigates it secretly and finds out the truth about her pregnancy. Yasuko cries and repents. Yasuko leaves the palace under the patronage of Empress Dowager Senshi and Michinaga (moved to his residence).source
In the Kingdom of France, Robert II, the son of Hugh Capet, was the first King of the Capetian royal dynasty.source
The Château de Goulaine vineyard was founded in France.source

May 17 – Ramwold, German Benedictine monk and abbotsource
September 9 – Olaf Tryggvason (or Olaf I), king of Norwaysource
Ahmad ibn Fadlan, Arab traveller and writer (approximate date)source
Huyan Zan, Chinese general of the Song Dynastysource
Masako, Japanese empress consort (born 950)source
Ivar of Waterford, Norse Viking king of Dublinsource
García Sáchez II, king of Pamplona (approximate date)source
Fantinus (the Younger), Italian hermit and abbotsource
Abu Sahl 'Isa ibn Yahya al-Masihi, Persian physiciansource
Abū Sahl al-Qūhī, Persian physician, mathematician and astronomersource
Ælfthryth, English queen and wife of King Edgar the Peaceful (approximate date)source
Abu-Mahmud Khojandi, Persian astronomer and Mathematics in medieval Islam/mathematiciansource
Barjawan, vizier and regent of the Fatimid Caliphatesource
Judah ben David Hayyuj, Moroccan-Jewish linguistsource