Ardanuç

City · c. 888 CE · in Europe

Capital of Kingdom of the Iberians (888–999).

Hotan (c. 888 CE): Capital of Kingdom of Khotan (888–1006).
Oltu (c. 888 CE): Capital of Kingdom of the Iberians (888–999).
Kars (c. 886 CE): Capital of Bagratid Armenia (886–1045).
Ani (c. 886–1319 CE): Capital of Bagratid Armenia (886–1045).
Bagaran (c. 886–1045 CE): Capital of Bagratid Armenia (886–1045).
Shirakavan (c. 886–1045 CE): Capital of Bagratid Armenia (886–1045).
Burgos (884 CE): Capital of Kingdom of Castile (1065–1235).
Jeonju (c. 892 CE): Capital of Hubaekje (892–935).
Kediri (879 CE): Capital of Kediri Kingdom (1046–1221).
Maragheh (c. 898 CE): Capital of Sajid Dynasty (898–929), Ilkhanate (1294–1335).

Around the same time and place

Abbasid Caliphate (750–1258 CE): The Abbasid dynasty, descended from Muhammad's uncle, took the caliphate from the Umayyads and ruled from Iraq, presiding over the Islamic Golden Age.
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.
Palmyra (c. 261–1929 CE): Capital of Palmyrene Empire (261–269).
Al-Khwarizmi (c. 780 CE – 850 CE): A Persian mathematician and astronomer at the House of Wisdom whose works introduced algebra and Hindu–Arabic numerals to later scholars; the word 'algorithm' derives from his name.
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.
Samarra (c. 836–892 CE): Capital of Abbasid Caliphate (836–892).
Al-Razi (c. 865 CE – 925 CE): A Persian physician and chemist from Rey who wrote influential medical encyclopedias and gave an early clinical description distinguishing smallpox from measles.