returning to france, in 1199 he negotiated the marriage of theobald iii of champagne to blanche of navarre. after theobald's death and during blanche's regency, he held great influence in the court at champagne. during the champagne war of succession he was part of a tribunal charged with ruling on the succession. in 1210 he led a detachment of crusaders in the albigensian crusade and participated in the siege of termes.