Plock

City · c. 1139 CE · in Europe

Capital of Duchy of Masovia (1139–1351).

Guimarães (c. 1139 CE): Capital of County of Portugal (1139–1143).
Sandomierz (c. 1139 CE): Capital of Duchy of Sandomierz (1139–1304).
Poznań (c. 1139 CE): Capital of Duchy of Greater Poland (1139–1304).
Mosul (c. 1139 CE): Capital of Zengid dynasty (1139–1250), Qara Qoyunlu (1375–1467).
Tinmel (c. 1139 CE): Capital of Almohad Caliphate (1139–1269).
Rabat (1146 CE): Capital of Morocco (1670–today).
Coimbra (c. 1147 CE): Capital of Kingdom of Portugal (1147–1256).
Halych (c. 1147 CE): Capital of Principality of Halych (1147–1199), Halych-Volhynia occupation (1199–1240), Principality of Galicia-Volhynia (1202–1240), and 1 more.
Paterna del Campo (c. 1147 CE): Capital of Taifa of Tejada (1147–1150).
Vaduz (1150 CE): Capital of Principality of Liechtenstein (1806–1814).

Around the same time and place

Council of Clermont (1095 CE): Pope Urban II called on Western Christians to aid Byzantium and take Jerusalem, launching the First Crusade.
University of Oxford (c. 1096 CE): Teaching existed at Oxford by 1096, making it the oldest university in the English-speaking world. It grew rapidly after Henry II barred English students from the University of Paris in 1167.
University of Paris (c. 1150 CE): Emerging around 1150 from the schools of Notre-Dame, the University of Paris became a leading centre of theology and philosophy in medieval Europe. Its college of the Sorbonne, founded in 1257, gave the university its popular name.
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.
Trier (16 BCE – 1618 CE): Capital of Electorate of Trier (1333–1618).
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.
Zagreb (1094 CE): Capital of Independent State of Croatia (1941–1944), Republic of Croatia (1992–today).