In 1683 the abbot of La Chaise-Dieu, Hyacinthe Serroni ordered the installation of an organ for the abbey church. He wanted a sumptuous baroque decor and called on the Flemish sculptor Jean Cox from Antwerp. The instrument was not completed until 1725. The originality of the buffets of the casadéen site leads us to study the evolution between the end of the Middle Ages and the beginning of the contemporary period of the buffets and organ stands, placing these creations in their liturgical context. The day will include a series of lectures from 10 am to 5 pm. It will end with a concert at 19:30, organ and choir to understand the organization of liturgies until the end of the Ancien Régime. At the organ, Jean-Luc Perrot, holder of the historic organ of Souvigny, with Yannick Berne choir conductor of the vocal ensemble Symphonia