As Rupert lacked the strength to proceed immediately to relieve York, it was agreed at a council of war in Oxford, the King's wartime capital, that he would first move into Lancashire to restore Royalist fortunes, use the Earl of Derby's influence to gather fresh recruits, and secure the port of Liverpool to allow communications with Royalist forces in Ireland.
Since Rupert was unable to immediately take action to relieve York, it was decided at a council of war in Oxford that he would first enter Lancashire to revive Royalist fortunes, utilize the influence of the Earl of Derby to gather new troops, and secure the port of Liverpool to facilitate communication with Royalist forces in Ireland.