Originally composed in Latin, The History of the Kings of Britain by Geoffrey of Monmouth claims to be a history of Britain’s kings from the island’s founding by Trojan descendent Brutus in 1200 BCE, to the Britons’ abandonment of the island in the seventh century CE. The text first appeared in the 1130s and was immediately popular, inspiring retellings and adaptations by writers and artists through the centuries. Because its historical merit is almost nonexistent, it has been called an epic in prose and treated as a literary text whose primary purpose is patriotic. It is credited with introducing the figure of Merlin and elevating King Arthur to mythic status.

This guide refers to the Penguin Classics edition translated by Lewis Thorpe. Noting that medieval divisions of the text were arbitrary, Thorpe divides the work into nine sections, including a dedication and eight parts titled by topic. The book begins with a dedication in which Geoffrey observes the conventions of the time by praising his patrons and expressing hope that his meager skills will be up to the task set before him. Part 1 concerns Britain’s founding by the great-grandson of Aeneas, who founded Rome after fleeing the fall of Troy. Brutus is exiled from his home, endures a period of wandering—during which time he liberates Trojans who have been enslaved by the victorious Greeks—and receives a prophecy to travel to an uninhabited island that will become Britain. Brutus’ genealogy and journey cement him as a figure comparable to ancient epic heroes and an heir to the Trojan legacy that links him to Rome. References to the Britons’ connection to Troy and Rome will recur throughout the text, implying their equal status to their Roman conquerors.

Part 2 covers the centuries between Britain’s founding and the Romans’ arrival. Geoffrey gallops swiftly through approximately 1,000 years of rulers, identifying succession and sharing anecdotes that lend authenticity and interest to the narrative. Among the many kings he discusses are brothers Belinus and Brennius who initially battle for the throne but ultimately make peace and combine forces to capture Rome, which becomes a significant detail that further legitimizes Britain’s view of itself as Rome’s equal.

Britain’s Roman era is the subject of Part 3. It takes Rome two years, three battles, and Briton’s betrayal to subdue Britain. Geoffrey maintains his focus on succession, cycling through the various kings and their fluctuating relationship with Rome. Also noted throughout this section is intermarriage between Romans and Britons that further blurs the lines between conqueror and conquered. The most notable ruler of this period is Maximianus, who becomes a cautionary tale about the danger of pursuing distant territories at the expense of the homeland’s security and stability.

The narrative focuses on a shorter length of time in Part 4 as it paves the way for Arthur’s appearance. Geoffrey discusses Arthur’s ancestors, including his grandfather Constantine and his father Utherpendragon. Between the two reigns, local leader Vortigern seizes power and seeks the help of magicians, bringing Merlin into the narrative. Geoffrey interrupts his narrative of kings to share Merlin’s prophecies, which appear as reported speech in Part 6. With at times obscure references, the prophecies are reminiscent of the New Testament book of Revelations. In Part 6, Geoffrey returns to the kings, examining the confrontation between Vortigern and Aurelius Ambrosius, Constantine’s son (and Arthur’s uncle). After Aurelius Ambrosius’ assassination, Utherpendragon assumes the throne. Having secured victory against his enemies, Utherpendragon returns home to feast and falls in love with Ygerna, who is already married to a British duke. Utherpendragon enlists Merlin to help him deceive Ygerna, and they conceive Arthur.

Arthur’s successful reign is the subject of Part 7. Crowned at 15, Arthur defeats local enemies, restores churches destroyed by Saxon pagans, marries Guinevere, and defies Roman demands for tribute. After defeating Roman troops, Arthur plans to attack Rome itself but cancels his expedition after hearing that his nephew Mordred has declared himself king and entered into an adulterous relationship with Guinevere. Hurrying home, Arthur battles and fells Mordred. Mortally wounded, Arthur relocates to the Isle of Avalon having done his duty.

Part 8 chronicles the Saxon domination of Britain, which comes about due to the Britons’ impiety and tendency for civil war. Famine and plague ravage the population, and the Saxons, who manage to avoid civil conflicts, take control of the island. The Britons’ conditions improve with the reigns of Cadwallo and his son Cadwallader. However, after the latter falls ill, the Britons again succumb to internal conflict. Cadwallader sails to Brittany, and an angel informs him that God no longer wants the Britons to rule the island. Cadwallader is ordered to do penance. The Britons will rise again at the time revealed in Merlin’s prophecies. With the Britons unable to recapture the island, the narrative concludes in the year 768.