Tintagel is a symphonic poem by Arnold Bax. It is his best-known work, and was for some years the only piece by which the composer was known to many concert-goers. The work was inspired by a visit Bax made to Tintagel Castle in Cornwall in 1917, and, although not explicitly programmatic, draws on the history and mythology associated with the castle.

–quoted from the Wikipedia article on Bax’s Tintagel

For more of his work, check out Wikipedia’s list of compositions by Arnold Bax. I myself am partial to his tone poems, though his symphonies are also excellent.