House of the Dragon has reorganized Westerosi power dynamics by positioning the Hightowers as dominant rulers of the Reach, departing from Game of Thrones canon where the Tyrells held that position. The HBO series makes the Hightowers the region's true power brokers during the Targaryen civil war, even though George R.R. Martin's source material establishes the Tyrells as the Reach's primary lords paramount.
This shift reflects the show's prequel timeline. House of the Dragon takes place roughly 200 years before Game of Thrones, and the narrative simply explains that the Hightowers held supremacy in that era before the Tyrells eventually rose to prominence. The creative choice strengthens the Hightower family's arc in the series, particularly through characters like Alicent and Otto Hightower, who become central figures in the Dance of the Dragons.
The Hightowers' Oldtown stronghold makes them natural candidates for regional dominance in the Targaryen period. Their connection to the Faith of the Seven and their accumulated wealth gave them leverage that the Tyrells would later leverage more effectively through strategic marriages and political maneuvering. By the time of Game of Thrones, roughly two centuries later, the Tyrells had consolidated enough power to become the Reach's undisputed lords.
This worldbuilding decision serves House of the Dragon's storytelling needs. Alicent's family becomes a faction unto itself rather than minor players supporting the Targaryen throne. Otto Hightower functions as a major power broker and schemer, and Alicent's Hightower identity carries real weight in court politics. The show deepens the family's historical significance without contradicting established lore, instead filling in gaps that Martin's books never explicitly addressed.
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