The viscount of Marsan addressed the inhabitants of these parishes, while announcing them his decision to build a fortress and of his desire of the there to see to participate, promising them the liberties in return for their contests to his defense.
The act that doesn't relate the circumstances of the foundation brings, however, no precision on the place of his implantation.
One only knows that Saint Peter inhabitants and Saint-Genès that were under the abbot's dominium of Saint-Sever didn't want to transport themselves without his agreement inside the castellum because he was situated on Saint Peter territory.
But, even though one admits that the site of confluence depended of Saint-Genès, insofar as it was about Saint Peter annex, by the expression Sancti-kneaded infra terminos, it is necessary to hear the parish and his annex undoubtedly: there is not therefore, to our opinion, no reason to think that the primitive castellum occupied another site that the one of the confluence of the Twelve and the Midou, where rose again at the end of the XVIIIéme century the vestiges of the old castle.
On the religious plan, the agreement made itself, it seems, enough quickly between the viscount and the abbot who received duty-free, inside the castellum, the site of a church and a house, as well as the recognition of its parochial rights.
But, the bishop of area having claimed the possession of the new church intra muros, he followed a violent quarrel with the abbot of Saint-Sever; finally, in 1141, the bishop gave up his pretensions in return for an indemnity of 130 soils morlans.
Otherwise, some difficulties seem to be been itself daylight when it was necessary to settle the temporal problems.
The abbot of Saint-Sever possessed, indeed, the justice on Saint Peter territory and discerned on every house of this castrum 6 d.
If he allowed his Saint Peter parishioners to get settled in the new castellum, he reserved the jurisdiction on them, in the same way, he seems, that on those of Saint-Genès that were of his alleu.
So, in a 1st time, the abbot of Saint-Sever kept some rights therefore on the inhabitants original of Saint Peter and Saint-Genès, enough quickly, however, the viscount was the only Lord justicier of the city, in the same way, when in 1270 he made grant to the Clarisseses of Beyries of the" sirmanatge ", royalties discerned on the soil of the city, he was the unique fundamental Lord of it.
The fact that the jurats of Mont de Marsan has, thereafter, taken oath on the altar of Saint-Pierre-of-mount recalled, however, the tie that united to his origins Mont de Marsan to the abbey of Saint-Sever as testify some again today the two keys that appear on the weapons of the city.
