Siege of Nicaea
The 1097 siege in which forces of the First Crusade and the Byzantine Empire captured Nicaea, then held by the Seljuk Sultanate of Rum.
Nicaea: A city in northwestern Anatolia, known in antiquity as Nicaea and today as İznik in Turkey. Its walls and nearby Lake Ascania made the city difficult to take by land alone.
People's Crusade: An unofficial 1096 expedition of mostly untrained European crusaders that was destroyed by Seljuk forces in Anatolia. Its defeat preceded the organized crusading armies that later besieged Nicaea.
Treaty of Devol: A 1108 agreement between Byzantine emperor Alexios I Komnenos and the Norman prince Bohemond of Taranto. Its provisions reflected Alexios’s broader effort to recover imperial lands, including territories gained after Nicaea.
Siege of Jerusalem (1099): The July 1099 siege in which First Crusade forces captured Jerusalem from Fatimid defenders. Unlike Nicaea, Jerusalem was taken by the crusaders themselves after a direct assault.
Lake Ascania: A freshwater lake beside İznik, historically called Lake Ascania. Seljuk boats on the lake kept the besieged city supplied until Byzantine forces brought boats overland.
Council of Clermont: A church council held in 1095 where Pope Urban II called for an expedition to aid eastern Christians and recover Jerusalem. Urban’s appeal set the First Crusade in motion, bringing its armies to Nicaea.
Battle of Dorylaeum: A 1097 battle in which crusaders defeated a Seljuk attack during their march across Anatolia. After Nicaea’s surrender, the crusader armies continued inland and fought at Dorylaeum.
Siege of Edessa: The 1144 siege in which Zengi captured Edessa, a crusader county, from its Frankish rulers. Nicaea’s surrender strengthened Byzantine control, while Edessa’s fall ended a crusader polity.
Alexios I Komnenos: Byzantine emperor from 1081 to 1118 who restored imperial power and negotiated with the First Crusade. He arranged the city’s surrender to Byzantine troops, preventing crusaders from taking it themselves.
Manzikert: A 1071 battle in which the Byzantine Empire suffered a major defeat against the Seljuk Turks. The battle accelerated Byzantine losses in Anatolia, including the eventual Seljuk capture of Nicaea.