First Barons' War

The Battle of Lincoln on 27 May 1217 was fought during the First Barons' War between royalist forces under William Marshal, William Longespée, Ranulf de Blondeville, Peter des Roches, and William de Ferrers on one side, and a French and rebel baronial force under Thomas, Count of Perche, Robert Fitzwalter, Saer de Quincy, Gilbert de Clare, and Henry de Bohun on the other. The French side committed a recorded force of 1,611. Beyond the engagement at Lincoln itself, no further detail on its conduct or outcome is supplied in the available record.

The Battle of Sandwich was the decisive naval engagement of the First Barons' War, cutting off the Capetian French forces supporting Prince Louis's campaign in England. The English fleet under Hubert de Burgh attacked and captured the French flagship along with most of the supply vessels commanded by Eustace the Monk and Robert of Courtenay. The loss of the flagship and the bulk of the supply fleet forced the remaining French vessels to withdraw to Calais, severing the logistical connection between Louis's land forces in England and their French base. By denying Louis the reinforcements and supplies the fleet was carrying, the battle effectively ended French prospects of sustaining the campaign, contributing directly to the collapse of the Capetian intervention and the conclusion of the First Barons' War.