The film is criticized by many historians for strengthening a propaganda myth of the Polish cavalry charging German tanks. In fact, the Polish cavalry never charged tanks, leave alone absurd slashing them with sabres. The main tactics of the cavalry was fighting on feet, and there were only several charges against infantry in 1939. On only one occasion, at Krojanty, the cavalry group was surprised by a fire of German armored cars, but did not try to charge them, and got away with moderate losses.
The film is roughly based on a novel "Lotna" by Wojciech Zukrowski, published in 1945.