Chernihiv

City · c. 1056 CE · in Europe

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.
Pereiaslav (c. 1056 CE): Capital of Principality of Pereyaslavl (1056–1239).
Azougui (c. 1056–1147 CE): Capital of Almoravid Dynasty (1056–1147).
Aghmat (c. 1058–1070 CE): Capital of Almoravid Dynasty (1058–1070).
Ouagadougou (1050 CE): Capital of Burkina Faso (1961–today).
Kangaba (1050 CE): Capital of Mali Empire (1236–1611).
Oslo (1048 CE): Capital of Kalmar Union (1402–1523), Denmark-Norway (1536–1814), Kingdom of Norway (1814–today).
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).

Around the same time and place

East–West Schism (1054 CE): Break in communion between the Church of Rome and the Church of Constantinople, dividing Catholic and Eastern Orthodox Christianity.
Varangians to the Greeks (c. 800–1100 CE): Scandinavian traders and warriors travelled from the Baltic up the Neva and Volkhov past Novgorod, portaged to the Dnieper and sailed down past Kiev to the Black Sea and Constantinople.
Basil II (958 CE – 1025 CE): Byzantine emperor, called the Bulgar Slayer, who conquered the First Bulgarian Empire and brought Byzantium to its medieval height.
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.
Olomouc (1017 CE): Capital of Margraviate of Moravia (1385–1414).
Suzdal (1024 CE): Capital of Principality of Rostov-Suzdal (1125–1240), Principality of Vladimir-Suzdal (1294–1389).
Gniezno (c. 1025 CE): Capital of Kingdom of Poland (1025–1385).
Sivas (c. 1094 CE): Capital of Danishmendids (1094–1178).