Claus Friedrich Bergen (18 April 1885 – 4 October 1964) was a German illustrator and painter, best known for his depictions of naval warfare in World War I.

He was raised in Munich, where, starting in 1904, he attended Moritz Weinhold's painting school and the Royal Academy of Fine Art, studying under Carl von Marr.

Continually printed and re-printed in books and periodicals, Bergen's depictions of the Old West, India, Arabia, and other exotic locales came to be widely associated with May's stories.

In June and July 1917, Bergen took the unprecedented step of joining the crew of the submarine U-53, under Kapitänleutnant Hans Rose, on an Atlantic combat patrol.

In the interwar period he painted numerous officially-commissioned large scale land- and seascapes, while his friendship with commanders such as Erich Raeder and Karl Doenitz led to continuing work for the German Navy.

Bergen's brother Otto was an aviator in the Great War, and the two were childhood friends of Ernst Udet, one of Germany's top fighter pilots.

The Nazis' counter piece to Guernica can be seen in the United Kingdom, as it was seized in 1945 by the British and, despite requests for restitution,[12] is held by the National Maritime Museum[13] in Greenwich, London.