When Did Erik Hazelhoff Roelfzema Die?

Siebren Erik Hazelhoff Roelfzema was a Dutch writer who became a resistance fighter and RAF pilot during the Second World War. Near the end of the war he was adjudant (assistant) to Queen Wilhelmina. He was made Knight 4th class of the Military William Order. He is perhaps best known for his book Soldaat van Oranje which described his experiences in the war. His book was later made into a film.