FITZWALTER, ROBERT (d. 1235), leader of the baro nial opposition against King John of England, served John in the Norman wars, and was taken prisoner by Philip of France, and forced to pay a heavy ransom. He was implicated in the baronial conspiracy of 1212. He was outlawed, but returned under a special amnesty after John's reconciliation with the pope. He continued, however, to take the lead in the baronial agitation against the king, and upon the outbreak of hostilities was elected "marshal of the army of God and Holy Church" (I215). He secured the support of the city of London. The famous clause of Magna Carta (§ 39) prohibiting sentences of exile, except as the result of a lawful trial, refers more particu larly to his case. He was one of the 25 appointed to enforce the promises of Magna Carta; and his aggressive attitude was one of the causes which contributed to the recrudescence of civil war (1215) . He was one of the envoys who invited Louis to England, and was the first of the barons to do homage when the prince entered London. Though slighted by the French as a traitor to his natural lord, he served Louis with fidelity until he was captured at the battle of Lincoln (May 1217) . Released on the conclusion of peace he joined the Damietta crusade of 1219, but returned at an early date to make his peace with the regency.