Urbain-Loir Mongazon was born in 1761 in Saumur. He became vicar of the parish of St. Martin in Beaupréau in 1786, then a middle school teacher. He refused to swear allegiance to the Republican Constitution in 1791. He took refuge in Vendée and then returned to his former parish at the Gâtine farm.
Throughout the period of the Infernal Columns, Mr. Mongazon eluded numerous searches. Withdrawn deep into the woods, he continued to visit his parishioners, going from house to house at night, then returning to the shelter of his hiding place before daybreak.
Hiding at the Gâtine farm, Mr. Mongazon was about to be arrested by Republicans. Surprised at the farm, he tried to return to his hiding place, but a thin layer of snow prevented him from concealing his escape. He owed his salvation only to the quick-wittedness of the shepherdess, who released her flock of sheep. This one, by trampling, erased the footprints in the snow and blurred the tracks.