A careful reader of the Historia will find that Geoffrey integrated 12th-century politics, culture, and society into his chronicle.
The beginning turbulence of the Anarchy and civil war, especially, have parallels within his chronicle, as do certain traits of the Norman court that appear in the courts of Arthur and other kings, and questions about legitimate queenship.
Thanks to the vast amount of invented historical material found in the Historia, there are plenty of opportunities for Geoffrey to incorporate contemporary 12th-century themes.
This is most likely one reason why Geoffrey wrote in the chronicle style. A medieval chronicle focused on “a year-by-year account of the actions of king and princes as well as the events, ''that take place as those years unfolded.”
15 Histories, on the other hand, were more like biographies, focusing on a single figure and the events of their life.
Attribution: Pringle, Andrew D. (2018) "The “Anarchy” of King Arthur’s Beginnings: The Politics that Created the Arthurian Tradition," Crossing Borders: A Multidisciplinary Journal of Undergraduate Scholarship: Vol. 3: Iss. 1.
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