Praying before relies of saints, according to hagiographie texts front Aquitaine and Gascony (XIth XIIIth centuries). The medieval Church excluded any idea of a direct link between the profane and the divine. Access to Christ, the dispenser of miracles and judge of salvation, takes place within a mediation space - the holy - which distinguishes the churches of the saints as being the « gates of Heaven » for those who are « friends of God ». Medieval hagiography, which records the words and deeds of the saints and praises the virtues of their relics (their ability to achieve miracles), makes it possible to observe the representations by clerics of the ways, through the intercessions of saints, by which prayers are submitted to Christ. Gascony of the 11th-13th centuries offers, from this point of view, a privileged observatory as a result of the strength of its hagiographical scriptoria, and of its inclusion in the networks of the great pilgrimage centres in the vicinity such as Rocamadour and Compostella. Hagiography, of which main function is its use for choir readings on the saint’s day, underlines the specific nature of clerical prayer : the lectio gives voice and body to a reliquary book of the words and deeds of the saint, in order to reveal his usefulness in the world. The clerical vocation of perpetual prayer is thus strongly developed. It relies upon powerful reciprocal ties which link the saint with his spiritual family. For the monk or canon, communal or personal prayer is exalted by the piety and obedience due to a saint who, in return, spares neither his companionship (comitas ) nor the beneficia that he can obtain from Christ. For the lay person, on the other hand, the rule of prayer demands a marked dissymmetry in the relationship (obedientia and humilitas ) ; praying to the saint requires ostentatious respect for the sacred. The word of the lay person thus counts for less than the totality of the corporeal and material conventions to which the application must conform (pilgrimage, sincerity of tears and sighs, listening to the office and pastoral manifestations, meditating broodingly in proximity to relics, offerings, payments to the saint, pacts sealed on the altar). Only the lay prayer of invocation, by which the faithful, in profane space, makes the relic of the nomen sancti their own, is the object of specific hagiographical treatment. L'invocatio indeed enables the churches to extend the range of effectiveness of their relics. It propagates above all the idea that the ubiquitousness of the actions of the saints can contribute to turning the whole of society to prayer, in order to heal itself from within of all the deviations which compromise the ideal of a society drawn together in one Church (heresies, private wars, insubordination of the militia, emancipation of both peasants and town dwellers).