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.
Perhaps the best known of all his orchestral works Bax’s Tintagel is a vivid tonal impression of the castle-crowned cliff of Tintagel in Cornwall. Here the legends of King Arthur and the scenic grandeur of the Atlantic Ocean fired Bax’s imagination into producing some of the most vivid sea music ever written. Bax himself wrote that the music brought, “…thoughts of many passionate and tragic incidents in the tales of King Arthur and King Mark… and that the piece ends as it began, with a picture of the castle still proudly fronting the sea and wind of centuries”
In case the linked video ever gets taken down, the above is information from the description, as it appears on the CD sleeve note for the performance by the Royal Scottish National Orchestra, conducted by David Lloyd-Jones. It is much better than the Wikipedia blurb above.