The trio was put together mainly to sing medieval polyphonic works, but has since early in their career expanded their repertoire to also include contemporary compositions, such as those of Gavin Bryars and Ivan Moody. Moody wrote the title track on their debut album "Words of the Angel" (2001), which reached the top ten of the Billboard Classical list.
Trio Mediæval's three members are Anna Maria Friman (from Sweden), and Linn Andrea Fuglseth and Torunn Østrem Ossum (from Norway). The group works closely with English tenor and vocal ensemble specialist John Potter. In 2014's Aquilonis, Berit Opheim appears in place of Torunn Østrem Ossum.