On 13 October 2017, James MacMillan’s 29-minute cantata The Sun Danced received its first performance in the Sanctuary of Fatima in Portugal. This was the 100th anniversary of what is claimed by the Catholic Church to have been the last in a cycle of apparitions of the Virgin Mary to three shepherd children in the Cova da Iria where, according to historical documentation, at least 50,000 people witnessed dramatic solar phenomena that to date remain unexplained. This chapter focuses primarily on the theological background to MacMillan’s compositional process, with particular reference to his choice of texts. These are highly unusual to the extent of being attributed by the children to a supernatural origin (the Virgin and the Angel of Portugal). The chapter will seek to explore how the work relates to the composer’s larger artistic and spiritual trajectory, to assess MacMillan’s purpose behind the writing of The Sun Danced, and to contextualize it with reference to other attempts by contemporary composers to take up the challenge of engaging with themes, positing the existence of an invisible spiritual realm and its interaction with human history and assessing the ‘mystical’ elements of the work in comparison to the musical mysticism of Olivier Messiaen.