While scouting locations in Budapest, Hungary, the Liberty Studios production team stopped in a café where the stars of BBC's Robin des bois (2006), including Jonas Armstrong, were relaxing. Little did they know, a year later, they would cast Armstrong as the lead role in this movie.
The working title was "The Glass House", because part of the movie takes place at the historical glass factory in Budapest, Hungary. It became a legation of the Swiss government during World War II. Many innocent lives were saved from the Nazi death camps by the covert missions that emanated from there.
The Hungarian government did not want to go to war with the Soviets. A few days after "Barbarossa" started, some aircraft in Soviet colors bombed some communities in eastern Hungary, and the Hungarians joined the war. Today, some think it was a German trick. In an article on a Polish aircraft in "Air International Magazine" wrapped things up with a comment that the Germans had captured some of these aircraft in flyable condition and used them to fake a Soviet bombing of Hungary.
The producers received small roles or cameos in this movie. Randy Williams can be seen as a Nazi officer in the restaurant scene, Christopher Williams played Jacob, the printer, and Brian Schmidt and Shaun Schmidt played Arrow Cross guards.
The U.S. declared war on German forces in Hungary, Bulgaria, and Romania on June 4, 1942. The bombing of the Ploesti oil fields in Romania in 1943 was to show that the U.S. was serious about the declaration of war.