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  ===Filming===
  English director Neil Marshall was aware of ''Game of Thrones'' from trailers and, given his experience with action and horror films, had unsuccessfully sought a directing role. About a week before shooting was to start, the episode's planned director had to leave the production because of a personal emergency, and a replacement had to be found quickly. Benioff and Weiss settled on Marshall on the basis of his work on ''Centurion'' and ''Dog Soldiers'', where he created intensive action sequences on a limited budget. Marshall began filming after two weeks of preparation, which included watching the show's first season. He avoided watching the Battle of Helm's Deep in ''The Lord of the Rings: The Two Towers'' as it was, according to Marshall, "an obvious comparison." He did, however, study such films as ''The Vikings'' and ''Kingdom of Heaven''.
  Benioff and Weiss described the episode's filming as "pretty much a month straight of night shoots." The cold and wet climate of Belfast was so uncomfortable for actors and extras, they said that their exhaustion from battle was no act, and weather machines were not required to simulate the wind and rain. The episode also has far more visual effects shots than any other. The special-effects department developed a catapult that fired bags of burning green napalm for the wildfire explosion, but decided to instead color regular fire green in post-production. Marshall took credit for many scenes of gore during the battle that the script did not describe in detail.