When Messiaen finished Trois petites liturgies de la présence divine (1943–4), almost all the orchestral works he had composed up to that point had been religious in ethos.1 There was no real sign that this would change: that he would stop devoting his orchestral works to the service of the Catholic faith. That some 20 years elapsed before he attempted another orchestral sacred work is intriguing. It was Couleurs de la cité céleste (1963) that broke the ice, and after it the orchestral and the sacred became once again closely united, as they had been in the pre-Turangalîla era. Couleurs also brought us his first obvious use of plainchant in an orchestral work, thus heightening the religiosity of this score to approximate that enshrined in Trois petites liturgies. And as Messiaen's fame continued to grow, the religious elements in his music grew with it, both in ubiquity and intensity. Retrospectively, sacred orchestral works composed after Couleurs exceed those before Trois petites liturgies not only in number, but also in magnitude, profundity and grandeur.