The village of Bassoues (Bassoa) is founded on the ground of an ancient forest, stay of druids. The latter celebrated the worship of the a divinity, replaced later by the god Mars, where the name Marsoulés comes which always exists in the locality. Time and civilization made disappear part of the primitive forests and the worship of saint Fris haste destruction of that of Bassoues, replaced by a city raised around of a sanctuary, more venerated of all the region. This is with the Moulin locality of l' Standard that saint Fry, nephew of Charles Martel, plant his banner to rejoin the Francs.
Crushed by Buckwheats on the heights of the village close to Lupiac, they oppose again to the enemy troops not far from Bassoues and leave this victorious time. The warlike value and the heroism of Fris saint are worth the posterity thus to it. But, reached an arrow mortal, it dies close to the Pont-au-Chrétien. Its body, buried with haste, is rediscovered two hundred years later, at the Xth century, by shepherds. Its relics are placed in a coffin of marble and a church is built in its honor. The fame and the “miracles” of the saint attract many pilgrims on via Tolosane of the ways of Saint-Jacques-of-Compostelle. In XIIIrd century, Bassoues becomes a country house, founded by the archbishops of Auch, owners of the grounds located around of a convent Benedictine. The keep, built about 1370 by the archbishop Arnaud Aubert, nephew of the Innocent pope VI, testifies nowadays to this time.