The Prelude and Postlude, WAB 126 by Anton Bruckner was written originally for organ in 1846. Bruckner was an extraordinary artist and is said to have been able to improvise at length on the organ. He was in demand throughout parts of Europe as an organist.
The Prelude is simple, serious, and solemn. The Postlude is Bach-like with a somber introduction followed by a formal Baroque-style fugue. - the publisher