The First Crusade (1096-1099) was a military expedition by Roman Catholic Europe to regain the Holy Lands taken in the Muslim conquests of the Levant (632-661), ultimately resulting in the recapture of Jerusalem in 1099. The first objective of their campaign was Nicaea, previously a city under Byzantine rule, but had become the capital of the Seljuq Sultanate of Rum under Kilij Arslan I. The siege lasted from May 14th to June 19th. Crusader armies besieging Nicaea are said to have catapulted diseased human heads into the city. After handing custody of Nicaea to the Byzantines, the crusaders resumed their march to Jerusalem.