Robert then participated in the Siege of Nicaea, after which the army was split into two groups. Robert marched with Stephen of Blois, Bohemond of Taranto, Robert Curthose, and the Byzantine guides, one day ahead of the rest of the crusaders. This army was surrounded by the Seljuk sultan Kilij Arslan at the Battle of Dorylaeum on 30 June 1097. The next day, the second army, led by Raymond IV of Toulouse, Godfrey of Bouillon, and Hugh of Vermandois, arrived and broke the encirclement; the two armies joined together, with Robert and Raymond forming the centre. The Turks were defeated and the crusaders continued their march.