Mosul

City · c. 1139 CE · in Europe

Capital of Zengid dynasty (1139–1250), Qara Qoyunlu (1375–1467).

Plock (c. 1139 CE): 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).
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

First Crusade (1096–1099 CE): Answering Pope Urban II’s call, armies of western knights marched to Constantinople, crossed Anatolia, took Antioch after a long siege and captured Jerusalem in July 1099, founding the crusader states.
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.
Knights Templar (c. 1119–1312 CE): Hugues de Payens and fellow knights founded this military order in Jerusalem around 1119 to protect pilgrims, with headquarters on the Temple Mount. It grew rich and powerful until Pope Clement V dissolved it in 1312 under pressure from Philip IV of France.
Saladin (c. 1137 CE – 1193 CE): Kurdish founder of the Ayyubid dynasty who became sultan of Egypt and Syria, defeated the crusaders at Hattin and retook Jerusalem in 1187.
Palmyra (c. 261–1929 CE): Capital of Palmyrene Empire (261–269).
Omar Khayyam (1048 CE – 1131 CE): Persian mathematician, astronomer and poet who solved cubic equations geometrically, helped reform the calendar, and is famed for the quatrains of the Rubaiyat.
Sivas (c. 1094 CE): Capital of Danishmendids (1094–1178).
Iznik (c. 1094 CE): Capital of Sultanate of Rum (1094–1307), Nicaean Empire (1206–1261).