Missa Solemnis (1920-21) is a monumental, hour-long work for choir, a quartet of vocal soloists, organ, piano, and celesta. The work was premiered in 1923 at Engelbrekt Church in Stockholm but has since been seldom performed. The work is now available on CD for the first time. This recording is part of the Swedish Musical Heritage project sponsored by the Royal Swedish Academy of Music. The goal of the project is to increase access to and promote the performance of hidden treasures from the Swedish repertoire. Erik Westberg Vocal Ensemble is one of Sweden’s leading choirs. The ensemble reaches a large audience thanks to a large number of commissioned works, an extensive audio catalog, and an international reputation. Andreas Hallén (1846-1925) was one of the most important persons in Swedish musical life from 1870 until his death. He was known contemporaneously as an orchestral, opera, and choral conductor in Gothenburg, Malmö, and Stockholm, as well as a critic and ultimately as professor in composition.