Perhaps as early as the end of the ninth century, some unknown French monk wrote what would be the most festive Kyrie of the Middle Ages: Tibi Christe supplices exoramus cunctipotens ut nostri digneris eleison. Tibi christe supplices is one of the three Kyries in the oldest Aquitanian troper, Pa 1240, the oldest West Frankish source for Kyries. Tibi christe supplices is probably one of the best known, and certainly the most elaborate and impressive Kyrie of the Aquitanian repertory. For three centuries, Tibi christe supplices was sung throughout Aquitania, as is attested by its numerous and widespread sources. In its French sources, the Kyrie melody Mel. 55 appears so regularly with the Latin text "Tibi Christe supplices" that the melody and the text seem closely identified. It also appears frequently with one or more tropes that stand outside the piece itself.