Kaliningrad

City · 1255 CE · in Europe

Capital of Duchy of Prussia (1526–1618).

Königsberg (1255–1945 CE): Capital of Duchy of Prussia (1526–1618), Brandenburg-Prussia (1619–1701).
Lisbon (c. 1256 CE): Capital of Kingdom of Portugal (1256–1910), Portuguese Empire (1502–1823), Portuguese Colonies (1564–1910), and 2 more.
Klaipeda (1252 CE): Capital of Kingdom of Prussia (1707–1708).
Glogow (c. 1250 CE): Capital of Duchy of Glogow (1250–1313).
Xacitarxan (1250 CE): Capital of Astrakhan Khanate (1468–1556).
Graz (c. 1260 CE): Capital of Duchy of Styria (1260–1501).
Chambéry (c. 1260 CE): Capital of County of Savoy (1260–1416).
Orange (c. 1260 CE): Capital of Principality of Orange (1260–1571).
Florence (c. 1260 CE): Capital of Republic of Florence (1260–1569), Grand Duchy of Tuscany (1797–1848), Kingdom of Etruria (1803–1806), and 1 more.
Brandenburg an der Havel (c. 1260 CE): Capital of Margraviate of Brandenburg (1260–1414), Electorate of Brandenburg (1422–1618).

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.
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.
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.
Dante Alighieri (1265 CE – 1321 CE): Florentine poet whose Divine Comedy, written in the Tuscan vernacular, is a masterpiece of world literature and helped establish the Italian language.
Giotto’s Scrovegni Chapel frescoes (1305 CE): Giotto covered the walls of a Padua chapel with the lives of the Virgin and Christ under a starry blue vault. His solid, feeling figures broke with Byzantine stiffness and began the road to the Renaissance.
Trier (16 BCE – 1618 CE): Capital of Electorate of Trier (1333–1618).
Fibonacci (c. 1170 CE – 1250 CE): Mathematician from Pisa who introduced Hindu–Arabic numerals to Europe; the Fibonacci sequence is named after him.