The central image of Lux Aeterna, as its title suggests, is that of light, and Mathias's language is well-equipped to evoke it. Shining, brazen fanfares and a glittering, gamelan-like use of harp and high-tuned percussion have always been characteristic sounds in his music, and they are imaginatively used here in one of his most striking recent scores. The plan of the work is ingenious, proceeding on three planes: that of the chorus, singing ritual and liturgical texts in Latin; that of the boys' choir, who sing Marian anthems in a simpler, slightly archaic, carol-like style; and that of the soloists, who are given three arias and a trio to words by St John of the Cross, sung in English. In each of the arias, the image of light is poetically fused with a further metaphor that can be readily paralleled in music: the contralto likens faith to the waves of a river, the mezzo-soprano sings of the flame of God's love, while the soprano is given St John's mysteriously beautiful lines about the soul's mystic marriage to Christ in a night cooled by a breeze among the cedars—water, fire and air. All three planes come together in the final section of the work, the chorus chanting the prayer that gives the cantata its title, the children's voices intoning the Ave maris stella hymn, the soloists left alone at the end with beautifully chiselled arching phrases, praying for the departed to be granted rest and eternal light.
The soprano aria is the emotional centre of the work, a sort of chaconne, with dark, slow-moving strings impressively conjuring up St John's ''dark night''; it rises to a fervently eloquent climax, crowned by an outburst of jubilance that is also typical of the composer: a rapid juxtaposition of fanfares, agitato strings and declamatory choral phrases chiming with brass. Similarly, the mezzo's 'fire' aria, bedecked with bell sounds, ends with a vision of peace and chaste love that culminates in a combination of the boys' choir singing an almost naively simple Ave regina coelorum with the main chorus surrounding the chant with radiant, static chords—a fine image of motionless contemplation of ''eternal light''.
The language of the work is immediately accessible and wholly personal: there are pages that can be compared to but scarcely demonstrated to derive from kindred moments in Britten, Tippett or Messiaen. There are passages that I am as yet not convinced by: the trio's hymn to the Trinity, with its curiously square rhythm, for example. But I have found already that it is a work that grows and deepens on repeated hearing, and much of the writing has a brusque urgency set alongside a luminous calm that are wholly appropriate parallels to St John's imagery.
The performance is a fine one, with particularly expressive singing from the soloists. The main chorus is a little recessed, perhaps not unfittingly, given its hieratic function, but I could have done with a degree or two more clarity in the otherwise successful and atmospheric recording.'