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. The book and the film about it eventually were made into the most successful Dutch musical ever, premiering 30 October 2010.

Wilhelmina was Queen of the Netherlands from 1890 until her abdication in 1948. She reigned for nearly 58 years, making her the longest-reigning monarch in Dutch history, as well as the longest-reigning female monarch outside the United Kingdom. Her reign saw World War I, the Dutch economic crisis of 1933 and World War II.