Smolensk

City · 863 CE · in Europe

Capital of Principality of Smolensk (1056–1406).

Brunswick (861 CE): Capital of Duchy of Brunswick (1815–1870).
Zaranj (c. 861 CE): Capital of Saffarid Dynasty (861–899).
Sibenik (860 CE): Capital of Kingdom of Croatia (926–1098).
Beiting (c. 860–1138 CE): Capital of Qocho Kingdom (860–1138).
Olbia (c. 866 CE): Capital of Giudicato of Gallura (866–1209).
Amol (c. 866 CE): Capital of Zaydi Alid dynasties (866–928), Ziyarid dynasty (936–979).
Porto Torres (c. 866 CE): Capital of Giudicato of Logudoro (866–1259).
La Seu d'Urgell (c. 870 CE): Capital of County of Urgell (870–1413).
Badajoz (875 CE): Capital of Taifa of Badajoz (1010–1151).
Sort (c. 875 CE): Capital of County of Pallars (875–1011), County of Pallars Sobirà (1040–1201).

Around the same time and place

Founding of Kievan Rus' (882 CE): Oleg of Novgorod took Kyiv and made it his capital, creating the state of Kievan Rus', which united East Slavic lands under the Rurik dynasty.
Cyrillic script (c. 893 CE): Scholars in the First Bulgarian Empire, probably at Preslav, built a Slavic alphabet mainly from Greek letters; Cyrillic now writes Russian, Ukrainian, Bulgarian, Serbian and many more.
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.
Nitra (c. 814 CE): Capital of Principality of Nitra (814–839).
Mission of Cyril and Methodius (863 CE): Byzantine brothers sent as missionaries to Great Moravia, who created the Glagolitic alphabet and translated the liturgy into Old Church Slavonic.
Hungarian conquest (c. 895 CE): Magyar tribes led by Árpád crossed the Carpathians and settled the Pannonian Basin, laying the foundation of the Hungarian state.
Székesfehérvár (c. 900 CE): Capital of Principality of Hungary (900–999), Kingdom of Hungary (1000–1543).
Esztergom (c. 900 CE): Capital of Principality of Hungary (900–999), Kingdom of Hungary (1001–1256).