 The scene with the drinking game between Tyrion , Bronn and Shae was written specifically for the episode , but the story of Tyrion 's ill @-@ fated marriage to Tysha was taken from a previous chapter of the books . Shae 's background was changed from Westerosi to foreign to accommodate Kekilli 's accent . Other notable divergence from the books include the modification of the whole strategy of Robb Stark when dividing his forces , and a change to the Targaryen genealogy as explained by Maester Aemon : in the TV adaptation the Mad King is described as the son , rather than the grandson , of Aegon V ( thus eliminating Jaehaerys II from the succession of kings ) . 
