As torrents in Summer from King Olaf

2 June 1857 – 23 February 1934

Scored for a cappella chorus, As Torrents in Summer is an excerpt from the epilogue of Sir Edward Elgar’s 1896 cantata, Scenes from the Saga of King Olaf, Op. 30.The text is an adaptation of a poem by Henry Wadsworth Longfellow which tells the story of Olaf Tryggvason, the medieval king of Norway, who brought Christianity to the Scandinavian country.

King Olaf (full title: Scenes from the Saga of King Olaf) is a cantata by the British composer Edward Elgar, scored for soloists, chorus and orchestra. It was commissioned for the North Staffordshire Music Festival of 1896, where it was well received. It went on to be performed by choral societies in other parts of the country.

Before the success of the Enigma Variations in 1899 consolidated his national reputation, Elgar was chiefly known for choral works such as The Black Knight and King Olaf. These early choral works have since been largely eclipsed, but King Olaf has been revived in recent years.

There are at least two recordings on CD and this one from the US which has a spoken introduction to the saga stories.
https://www.youtube.com/watch?v=-CwlwBYc2YA&t=10s