Jaca

City · c. 830 CE · in Europe

Capital of County of Aragon (830–921).

Heraklion (c. 830 CE): Capital of Emirate of Crete (830–960).
Aínsa (c. 825 CE): Capital of Kingdom of Sobrarbe (825–829).
Samarra (c. 836–892 CE): Capital of Abbasid Caliphate (836–892).
Mashhad (818 CE): Capital of Afsharid Iran (1736–1756).
Nitra (c. 814 CE): Capital of Principality of Nitra (814–839).
Kashgar (c. 850 CE): Capital of Kara-Khanids (850–1045), Eastern Kara-Khanids (1046–1138), Western Karakhanid Khanate (1046–1084), and 4 more.
Palermo (c. 850 CE): Capital of Emirate of Sicily (850–1091), Kingdom of Sicily (1139–1266), Kingdom of the Two Sicilies (1815–1860).
Balasagun (c. 850–1218 CE): Capital of Kara-Khanids (850–1045), Eastern Kara-Khanids (1046–1138), Western Karakhanid Khanate (1046–1084), and 1 more.
Gangaikonda Cholapuram (c. 850 CE): Capital of Chola Empire (850–1259).
Yasodharapura (c. 802–1431 CE): Capital of Khmer Empire (802–1431).

Around the same time and place

Charlemagne (c. 747 CE – 814 CE): King of the Franks who conquered much of Western Europe, was crowned emperor in 800 and promoted a revival of learning, the Carolingian Renaissance.
Reconquista (718–1492 CE): Centuries-long series of campaigns by Christian kingdoms to take the Iberian Peninsula from Muslim rule, ending with the fall of Granada in 1492.
Viking raid on Lindisfarne (793 CE): Viking raid on the monastery of Lindisfarne in Northumbria, conventionally taken as the beginning of the Viking Age.
Coronation of Charlemagne (800 CE): Pope Leo III crowned Charlemagne emperor in St Peter's Basilica on Christmas Day, reviving the imperial title in the West.
Trier (16 BCE – 1618 CE): Capital of Electorate of Trier (1333–1618).
Great Mosque of Córdoba (785 CE): Mosque begun by Abd al-Rahman I in 785, famous for its forest of double-arched columns; it was converted into a cathedral in 1236.
Fez (789 CE): Capital of Idrisids (793–974), Marinid Sultanate (1250–1465), Wattasid dynasty (1472–1554), and 1 more.
Book of Kells (c. 800 CE): Lavishly illuminated Gospel book, probably begun at Iona and kept for centuries at the abbey of Kells; a masterpiece of Insular art.