Martin, but a significant amount of material was also added from the fourth and fifth books, A Feast for Crows and A Dance with Dragons, which run concurrently but follow different sets of characters. Season 4 is mostly based on the second half of A Storm of Swords, the third book in the A Song of Ice and Fire series by George R.R.
Weiss returned as showrunners, having signed a new two-year contract with HBO prior to the commissioning of the third season. It concluded filming on November 21, 2013. It consists of ten episodes and began filming on July 8, 2013. However, significant pre-production work on the season had already taken place previously to this point, including the writing of at least six of the scripts (by March 2013), and the booking of some of the filming dates.
The fourth season of Game of Thrones was formally commissioned by HBO on April 2, 2013, following a substantial increase in audience figures between the second and third seasons.
