Born in 1867 in Berlin, died 1930 in Dusseldorf. German painter and etcher. He had several successful exhibitions in 1907 and 1908. He is registered in several German art lexicons (Thieme –Becher, Dressler, 1937 etc.)
- Thielen visited Macedonia during the First World War, likely as military painter. His ink drawings from the villages of Opaje, Negorci and Kurbevica were reproduced as front-line postcards.