On 4 March Warwick proclaimed the young Yorkist leader as King Edward IV. The country now had two kings — a situation that could not be allowed to persist, especially if Edward were to be formally crowned. The young king summoned and ordered his followers to march towards York to take back his family's city and to depose Henry formally through force of arms. On 28 March, the leading elements of the Yorkist army came upon the remains of the crossing in Ferrybridge crossing the River Aire. They were rebuilding the bridge when they were attacked and routed by a band of about 500 Lancastrians, led by Lord Clifford. Learning of the encounter, Edward led the main Yorkist army to the bridge and was forced into a gruelling battle. The Lancastrians retreated but were chased to Dinting Dale, where they were all killed, Clifford being slain by an arrow to his throat.