Kalisz

City · c. 1210 CE · in Europe

Capital of Duchy of Kalisz (1210–1219).

Naxos (c. 1210 CE): Capital of Duchy of the Archipelago (1210–1313).
Dresden (1206 CE): Capital of Electorate of Saxony (1547–1805), Kingdom of Saxony (1806–1808).
Auch (c. 1206 CE): Capital of County of Armagnac (1206–1496).
Trabzon (c. 1206 CE): Capital of Empire of Trebizond (1206–1461).
Poitiers (c. 1206 CE): Capital of County of Poitou (1206–1249).
Arta (c. 1206 CE): Capital of Despotate of Epirus (1206–1479).
Xanadu (c. 1206–1439 CE): Capital of Mongol Empire (1206–1293), Northern Yuan (1375–1439).
Avarga (c. 1206 CE): Capital of Mongol Empire (1206–1235).
Andravida (c. 1206 CE): Capital of Principality of Achaea (1206–1432).
Banda Aceh (1205 CE): Capital of Sultanate of Aceh (1516–1903).

Around the same time and place

Magna Carta (1215 CE): Charter agreed by King John at Runnymede that limited royal power and became a foundation of constitutional law in the English-speaking world.
Notre-Dame de Paris (1163 CE): Gothic cathedral on the Île de la Cité, begun in 1163, famous for its flying buttresses, rose windows and sculpture.
Francis of Assisi (c. 1181 CE – 1226 CE): Italian friar who embraced radical poverty and founded the Franciscan Order; one of the most venerated saints of Christianity.
Sack of Constantinople (1204) (1204 CE): Armies of the Fourth Crusade sacked Constantinople and set up a Latin Empire, permanently weakening Byzantium.
Thomas Aquinas (1225 CE – 1274 CE): Dominican friar and theologian whose Summa Theologica synthesised Aristotelian philosophy with Christian doctrine.
Mongol invasion of Rus’ and Europe (1236–1242 CE): Mongol armies under Batu and Subutai conquered Volga Bulgaria and the Rus’ principalities, destroyed Kiev in 1240, and in 1241 won at Legnica and Mohi, before withdrawing from Central Europe in 1242.
Mongol invasion of Kievan Rus' (1237–1242 CE): Mongol armies under Batu Khan destroyed Ryazan, Vladimir and Kyiv, subjecting the Rus' principalities to Mongol overlordship for over two centuries.
Trier (16 BCE – 1618 CE): Capital of Electorate of Trier (1333–1618).