The Three Choirs festival regularly includes the staples of the choral repertory, but it also makes a point of exploring its more neglected corners, too, especially works it brought into existence in the first place. William Mathias’s Lux Aeterna was commissioned for the 1982 festival in Hereford; and performed there again in 1994 in memory of Mathias, who had died in 1992. Revived again this year, it stood up well – an ambitious, hour-long piece, part requiem (dedicated to the memory of the composer’s mother), part a wider celebration of divine light, using texts culled from a variety of liturgical sources including the requiem mass and the vespers for Trinity Sunday, as well as English versions of poems by St John of the Cross.

Each of the three parts is centred on a setting of one of those poems, sung by the solo contralto, mezzo and soprano in turn, framed by the adult and boys choirs. The first two sections are strikingly effective, with their shimmering washes of sound around the voices conjuring up images of eternal light, but the much longer third part loses its way a bit, and a trio for the three soloists (Sarah Fox, Jennifer Johnston and Claudia Huckle) goes on too long before the affirmative ending. Yet the performance under Peter Nardone certainly made the most of the shining moments, and showed that it well deserved its revival.

Before it there had been a 150th-birthday tribute to Nielsen with a performance of his Hymnus Amoris, a piece that in the UK at least tends only to be heard in anniversary years such as this. While the composer of its orchestral opening is instantly recognisable, the choral writing that follows is much more anonymous, though this rather dogged performance under Nardone, with Fox joined by Robert Murray, David Stout and Barnaby Rea as the soloists, didn’t really give it the clarity it needs.

• The Three Choirs festival ends on 1 August. Box office: 0845 652 1823.