Dom Alan Rees (1941–2005) was a Welsh Benedictine monk, priest, abbot, and celebrated liturgical composer. Born in Morriston, Swansea, to Baptist and Anglican parents, he grew up steeped in the rich Welsh hymn-singing tradition, which profoundly shaped his lifelong vocation as a church musician. Received into the Catholic Church while studying music at University College Cardiff, he graduated in music, earned a postgraduate diploma in education, and qualified as ARCM (1961) and ARCO (1964).

After a nervous breakdown prevented entry to Ampleforth Abbey, he taught briefly before becoming choirmaster and organist at Cardiff’s St David’s Cathedral (1963–1968). In 1968 he entered Belmont Abbey, studied theology in Rome, and was ordained priest in 1974. He served Belmont as choirmaster (1972–2005), novice master (1982–1986), and was elected ninth abbot (1986–1993). Disliking authority and battling depression, he resigned in 1993, receiving the honorary title Abbot of Tewkesbury, and continued giving retreats and serving as Vicar for Religious in Cardiff Archdiocese.

Renowned internationally for his Gregorian-inspired compositions, his Papal Mass was sung at Pope John Paul II’s historic 1982 visit to Cardiff. His works remain in use worldwide. He founded the Panel of Monastic Musicians, chaired the Society of St Gregory (1981–1985), collaborated with ICEL, and published Prayers from the Cloister (1996).

After recurrent depression, Dom Alan died on 2 October 2005, aged 64, following a fall from a balcony at Belmont Abbey.