Of the iconographic programme which used to decorate the apse of the cathedral of St Lizier at its origin (1078), there remain : a Majestas Domini, in the semi dome (remade in the 13th century), eight apostles arranged in pairs, each under a blind arcade, and, lower, five scenes of Christ’s childhood : the Magi before Herod, the Adoration of the Magi, the Annunciation, the Visitation and the Nativity. The male heads placed in the corner-pieces of the arcades, the female heads which adorn the frieze separating the two registers of the apse, and the ornamental bands which follow the form of the arches, complement this decor. The representations of the apostles were placed between the images relating to the Incarnation and the theophany of Christ, giving without doubt a particulary significant thematic emphasis to this programme. Chronologically, they belong to the most ancient occurrences of an iconographie family which later became very typical of the Pyrenees region. From the point of view of typology, they are distinguished from the majority of examples by their twin placing and by their strictly frontal poses. It seems that to insist thus on the representation of the college of apostles presided over by Saints Peter and Paul, witnessed to the desire to raise the theme of the apostolic roots of the Church. This latter is shown here between the first coming of Christ and his eternal triumph. The apostolicity of the Church is found at the centre of the concerns of the partisans of the reform. One of the important forums for this movement in the Pyrenees region was exactly the cathedral of St Lizier.