Siege of Nicaea

Nicaea, a walled city on the shore of Lake Ascanius in northwestern Anatolia, served as the capital of Kilij Arslan I, sultan of the Seljuk Sultanate of Rum. In May 1097 the armies of the First Crusade, ferried across the Bosporus with Byzantine assistance, invested the city. It was the crusade's first major operation, undertaken in cooperation with the emperor Alexios I Komnenos, to whom the crusade's leaders had sworn oaths regarding former imperial territory.

Kilij Arslan was absent when the siege began, campaigning in eastern Anatolia against the Danishmend Turks over the city of Melitene; his treasury and family remained inside Nicaea. Having underestimated the size and seriousness of the crusader host, he returned by forced marches and attacked the besiegers' southern positions on 21 May. The relief attempt failed against superior numbers, and the sultan withdrew into the interior, leaving the garrison to its own devices.

The city's western wall fronted the lake, which kept it supplied and uncaptured until Alexios had boats hauled overland and launched on the water, closing the last route in mid-June. Cut off, the garrison negotiated with Byzantine representatives rather than with the crusader princes, and on 19 June 1097 the city surrendered directly to imperial officers. Crusaders were admitted only in small escorted groups, and the city was spared a sack, an arrangement that protected the inhabitants but fed lasting resentment between the Latin leadership and the emperor. A week later the crusade marched east; Kilij Arslan attacked the leading column at Dorylaeum on 1 July and was again defeated. He abandoned the western plateau, moving his capital inland to Konya, and the Byzantines recovered Nicaea and the Aegean coastlands after sixteen years of Seljuk rule.