The 10 most significant kings to rule Westeros

6. Joffrey Baratheon (298 AC – 300 AC)

Spoiled, cruel, and psychotic, Joffrey Baratheon was the product of incest like so many other kings of Westeros. While officially he was the son of Robert Baratheon, Joffrey was, in fact, the outcome of an affair between Cersei Lannister and her twin brother Jamie. While nobody would ever suggest that Joffrey was a good king, few could dispute he was a significant one. Indeed, his mere existence led to an all-out war.

While Joffrey bears no responsibility for the events that initially started Westeros on the road to the War of the Five Kings — Jon Arryn being murdered by his sister Lysa at the behest of Petyr “Littlefinger” Baelish — there is no doubt that he is an usurper. The Lannisters always knew that Joffrey had no right to be King and that Stannis Baratheon was his brother Robert’s true heir. Knowing they must secure power, Joffrey packed the small council with his Lannister kin and allies, alienating houses already uneasy over the power of Casterly Rock. With the Seven Kingdoms already on the brink, his execution of Eddard Stark turned a spark into an inferno.

"“I have dreamed of giving up the crown. Take ship for the Free Cities with my horse and my hammer, spend my time warring and whoring; that’s what I was made for. The sellsword king, how the singers would love me. You know what stops me? The thought of Joffrey on the throne, with Cersei standing behind him whispering in his ear.” — Robert Baratheon, A Game of Thrones"

Joffrey’s insanity undoubtedly had to potential to eclipse that of even the Mad King Aerys II. While his murder at the hands of Littlefinger and Olenna Tyrell wasn’t done for altruistic reasons, there is no doubt it was necessary.

Joffrey’s actions eventually have a significant impact on the downfall of Houses Lannister and Baratheon. While both survive, it will undoubtedly be centuries before either rise again to the levels seen before the reign of Joffrey.