Guy I de Lévis , Lord of Mirepoix and Marshal of the faith became famous during the Albigensian crusade as a lieutenant of his Overlord Simon IV de Montfort.
Guy came from the House of Lévis. His father, Philippe de Lévis was the founder of the lineage.
He married Jeanne de Voisins or Guiburge.
They were the parents of:
Jeanne (1205-1284), married Philippe II de Montfort (died 1270), Lord of Castres.
Guy II (1210-1247), his heir.
In 1209, answering the call for the crusade launched by the Pope, he placed himself under the orders of Simon de Montfort and played an active part in the Albigensian crusade. He participated in the siege of Béziers. Soon after, Simon de Montfort, prodigal with his close lieutenants, gave him the seigneury of Mirepoix, which included the territories conquered by the Crusaders in Languedoc. Guy de Lévis took the title of Marshal of the faith or Marshal of the crusade.
He participated also in the siege of Beaucaire in 1216 and Toulouse which began in September 1217 and where Simon de Montfort was killed.
The Treaty of Paris of 1229 confirmed this set of possessions since article 15, provided that the land of Marshal is left to Guy de Lévis. He was thus awarded again the land of Mirepoix and the country of Olmes took on the area of the County of Foix. Based on this Act, the House of Lévis will be in the region for seven centuries.
Guy de Lévis died in 1233; He was buried in l'abbaye de Notre-Dame de la Roche de Lévis-Saint-Nom which he had founded.