Frants Diecke Cappelen Beyer (9 May 1851 - 10 November 1918) was a Norwegian average adjuster, tax inspector and composer. He is particularly known for his long-term close friendship with composer Edvard Grieg. A large portion of the letter correspondence between Grieg and Beyer has been preserved and later published.[1] Among his musical contributions are records of eighteen folk songs which formed the basis for Grieg's opus 66.[2] He was chairman of the board of the Bergen Philharmonic Orchestra for many years.[1]