Geoffrey starts the book with a short dedication. He claims that he was given a source for the time period by Archdeacon
Walter of Oxford, who presented him with a "certain very ancient book written in the British language" from which he has translated his history.
Books 1–3 The
Historia begins with the
Trojan hero
Aeneas, who, according to the
Aeneid, settled in Italy after the
Trojan War. His great-grandson
Brutus is banished, and, after a period of wandering, is directed by the goddess
Diana to settle on an island in the western ocean. Brutus lands at
Totnes and names the island "Britain" after himself, defeating the previous giant inhabitants. He establishes the city that was eventually renamed London. After Brutus' death, the island is divided into three kingdoms, each given to one of his sons:
Loegria (England) to
Locrinus,
Cambria (Wales) to
Camber, and
Alba (Scotland) to
Albanactus. Centuries later, Locrinus' descendant
King Leir divides his kingdom among his three daughters,
Goneril,
Regan and
Cordelia. However, because of a slight, he gives Cordelia no land, whereupon she departs for Gaul. Leir later regrets his actions towards Cordelia and travels to Gaul. Cordelia helps raise a Gaulish army for Leir, who returns to Britain, defeats his sons-in-law and regains the kingdom. Cordelia inherits the throne and rules for five years until
Cunedagius and
Marganus (sons of her two sisters) rebel against her. They imprison Cordelia; grief-stricken, she kills herself. Ending a civil war, Cunedagius eventually kills Marganus in Wales. In a later era,
Dunvallo Molmutius, the son of Cloten, the
King of Cornwall, establishes his rule over the whole island. He is said to have established the
Molmutine Laws. Dunvallo's sons,
Belinus and
Brennius, fight a civil war before being reconciled by their mother, and proceed to sack
Rome. Victorious, Brennius remains in Italy, while Belinus returns to rule Britain. Numerous brief accounts of successive kings follow.
Books 4–6 After his conquest of Gaul,
Julius Caesar looks over the sea and resolves to order Britain to swear obedience and pay tribute to Rome. Cassivellaunus pays tribute and makes peace with Caesar, who then returns to Gaul. He dies and is succeeded by his nephew Tenvantius. Tenvantius' grandson Guiderius refuses to pay tribute to emperor
Claudius, who then invades Britain. After
Guiderius is killed in battle with the Romans, his brother
Arvirargus eventually agrees to submit to Rome, and is given the hand of Claudius's daughter Genvissa in marriage. The line of British kings continues under Roman rule. When Octavius passes the crown to his son-in-law
Maximianus, his nephew
Conan Meriadoc is given rule of Brittany to compensate him for not succeeding. After a long period of Roman rule, the Romans decide they no longer wish to defend the island and depart. The Britons are immediately besieged by attacks from
Picts, Scots and Danes. In desperation the Britons send letters to the general of the Roman forces, asking for help, but receive no reply. The Britons ask the King of Brittany,
Aldroenus, descended from Conan, to rule them. However, Aldroenus instead sends his brother
Constantine to rule the Britons. After Constantine's death,
Vortigern assists his eldest son
Constans in succeeding, before enabling their murder and coming to power. Constantine's remaining sons
Aurelius Ambrosius and
Uther are too young to rule and are taken to safety in Brittany. Vortigern invites the
Saxons under
Hengist and
Horsa to fight for him as mercenaries, but they rise against him. He loses control of much of his land and encounters
Merlin.
Book Seven: The Prophecies of Merlin At this point Geoffrey abruptly pauses his narrative by inserting a series of prophecies attributed to
Merlin. Some of the prophecies act as an
epitome of upcoming chapters of the
Historia, while others are veiled allusions to historical people and events of the
Norman world in the 11th–12th centuries. The remainder are obscure.
Books 8–12 After
Aurelius Ambrosius defeats and kills
Vortigern, becoming king, Britain remains in a state of war under him and his brother Uther. At one point during the continuous string of battles, Ambrosius takes ill and Uther must lead the army for him. A comet taking the form of a dragon's head (
pendragon) appears in the night sky, which Merlin interprets as a sign that Ambrosius is dead and that Uther will be victorious and succeed him. But another enemy strikes, forcing Uther to make war again. This time he is temporarily defeated, gaining final victory only with the help of
Duke Gorlois of Cornwall. But while celebrating this victory with Gorlois, he falls in love with the duke's wife,
Igerna. This leads to war between Uther Pendragon and Gorlois of Cornwall, during which Uther clandestinely lies with Igerna through the magic of Merlin.
Arthur is conceived that night. Then Gorlois is killed and Uther marries Igerna. Uther's son
Arthur assumes the throne and inflicts a severe enough defeat against the Saxons that they cease to be a threat until after his death. He conquers most of northern Europe and ushers in a period of peace and prosperity that lasts until the Romans, led by
Lucius Hiberius, demands that Britain once again pay tribute to Rome. Arthur defeats Lucius in Gaul, intending to become Emperor, but in his absence, his nephew
Mordred seduces and marries
Guinevere and seizes the throne. Arthur returns and kills Mordred at the
Battle of Camlann, but, mortally wounded, he is carried off to the isle of
Avalon, and hands the kingdom to his cousin
Constantine, son of
Cador and Duke of Cornwall. The Saxons return after Arthur's death, but would not end the line of British kings until the death of
Cadwallader. Cadwallader is forced to flee Britain and is told by an angel that Britons will no longer rule. He dies in Rome, leaving his son and nephew to rule the remaining Britons, driven into Wales. The Saxon Athelstan becomes King of Loegria. ==Sources==