This splendid fragment corresponds to a lacuna in the famous manuscript from the Cluny lectionary, kept in the National Library. Of unusual dimensions, the manuscript presents on one side a column of liturgical text and on the other a painting illustrating the Ascension of Christ. The lectionary is the choir book which contains the lessons that are read during mass or in the refectory. In it can be found the Gospels with commentaries by the Fathers of the Church.

Occupying the whole height, the scene of the Ascension of Christ is the biggest painting and one of the best preserved. Around the outside of the manuscript runs a triple frame, with gold on the outside and pewter in the inside, and between these two is a third band made up of various coloured sections of ornamentation. The scene composition, on two levels, lends a powerful dynamic to the image. In the lower part, the Virgin, is depicted in the centre, in a chequered niche, surrounded by the apostles. They are all raising their hands and their eyes to Heaven. In the top part is a triumphant Christ, standing facing us, a sceptre in his hand, and giving a blessing. He is dressed in a coat whose beautifully drawn edges extend beyond the vesica, and stand out from the intense blue of the background. He is surrounded by a vesica framed with a double line, whose point encroaches into the golden frame of the picture. Between the two scenes, as mediators between the terrestrial world and the celestial world are the busts of two angels with multicolored wings.

This manuscript is the only important sign left in the field of manuscripts of the splendour once found in Cluny. Its execution constitutes one of the most fascinating proofs of the penetration of the Byzantine style into the Western European paintings of this era.