Olaf ("the Norseman") Sondergaard was a 23rd century Human Starfleet officer. Sondergaard was known for his service as a starship captain, where he gained his nickname based on his descent from northern European stock. By the 2260s, Sondergaard was an admiral serving at Starfleet Command. In 2268, Sondergaard was impersonated by Singa in a message sent to the USS Enterprise, ordering that vessel to divert to Raga's Planet. (TOS short story: "The Sleeping God")