A scion of a noble family in Champagne, and invested with the title of seneschal of that county, he spent his early years at the court of Thibaut IV, Count of Champagne, a poet and king of Navarre, and of the kings of France. He took part in the Sixth Crusade (1248-50), sharing with St. Louis IX (v.) the hardships of war and imprisonment. After his ransom (1251), he advised St. Louis to remain in the East, and with him returned to France in 1254, continuing to assist him in matters of government. Charged by St. Louis’s successor, Philip III, with the administration of the County of Champagne (held by Joan I of Navarre, who later became queen of France through her marriage to Philip IV), he retained this office until an advanced age.
At the request of Joan I herself, he composed (1305-1309) the *Histoire de saint Louis*. For this celebrated chronicle of the time he is regarded as the second of the great historians of French medieval times, after Villehardouin and before Froissart. For it he drew upon his own memories as a companion of the king and as a witness (1282) at the process for his canonization, as well as on documents from the archives of St-Denis and on other written and oral accounts, weaving all this together with a remarkable freshness and sincerity, attentive to every detail of life and to every nuance of the chivalric and religious sentiments of his age, for which the *Histoire* remains a primary document.