LDV49.1

71 LOUIS THIRY I will not touch on the delicate question of the relationship between Olivier Messiaen’s music and the mysteries suggested by the titles he chose: they combine a deeply sincere inspiration (of which there is nothing to be said) and a naive symbolism linked to a kind of numerological esotericism. Messiaen expressed himself abundantly on this subject. He has sometimes been criticised for that, but was he not the only one with the authority to comment on his works? However, the question of what words can say about music remains open: is not the mystery concealed in a simple prelude surrounded by silence as profound as the mystery that the most elaborate commentary claims to explain? It is interesting to examine the evolution of Olivier Messiaen’s language in his organ works. It is situated in the more general framework of the history of his musical language as a whole and can be roughly described as follows: ‘Modality’, ‘Dodecaphony’ (from which modality is not entirely absent) and ‘Return tomodality’ (sometimes in an extreme way, as in the use of Gregorian chant in his last great organ cycles). It is possible to distinguish twomain sources for Messiaen’s conception of the organ: the teaching of Marcel Dupré and the organ of La Trinité.