Oslo

City · 1048 CE · in Europe

Capital of Kalmar Union (1402–1523), Denmark-Norway (1536–1814), Kingdom of Norway (1814–today).

Ouagadougou (1050 CE): Capital of Burkina Faso (1961–today).
Kangaba (1050 CE): Capital of Mali Empire (1236–1611).
Nishapur (c. 1040 CE): Capital of Great Seljuk Empire (1040–1194).
Ronda (c. 1040 CE): Capital of Taifa of Ronda (1040–1065).
Hamadan (c. 1040 CE): Capital of Great Seljuk Empire (1040–1194).
Tremp (c. 1040 CE): Capital of County of Pallars Jussà (1040–1191).
Silves (c. 1040 CE): Capital of Taifa of Silves (1040–1063).
Morfil (c. 1040 CE): Capital of Takrur (1040–1235).
Chernihiv (c. 1056 CE): Capital of Principality of Chernigov (1056–1240).
Volodymyr (c. 1056 CE): Capital of Principality of Volhynia (1056–1201), Halych-Volhynia occupation (1199–1240), Principality of Galicia-Volhynia (1202–1240), and 1 more.

Around the same time and place

William the Conqueror (c. 1028 CE – 1087 CE): Duke of Normandy who conquered England in 1066 and became its first Norman king.
Battle of Hastings (1066 CE): William, Duke of Normandy, defeated and killed King Harold II, beginning the Norman conquest of England.
University of Oxford (c. 1096 CE): Teaching existed at Oxford by 1096, making it the oldest university in the English-speaking world. It grew rapidly after Henry II barred English students from the University of Paris in 1167.
Trier (16 BCE – 1618 CE): Capital of Electorate of Trier (1333–1618).
Stephen I of Hungary (c. 975 CE – 1038 CE): First king of Hungary, crowned in 1000 or 1001, who converted his people to Christianity; venerated as Saint Stephen.
Cnut the Great (c. 990 CE – 1035 CE): Danish prince who became king of England, Denmark and Norway, ruling a North Sea empire.
Beowulf (c. 1000 CE): Old English epic poem about the hero Beowulf, surviving in a single manuscript from around 1000; the most important work of Old English literature.
Wroclaw (1000 CE): Capital of Duchy of Silesia (1139–1304), Duchy of Wroclaw (1169–1201).