This poem is twenty thousand lines long, and relates the adventures and life of Brutus, the great-grandson of Aeneas.
At the time of Brutus' birth his parents were frightened by an oracle predicting that he would be the cause of the death of both parents, and only after long wanderings would attain the highest pitch of glory.

This prophecy was duly fulfilled.

Brutus' mother, a niece of Lavinia, died at his birth.

Fifteen years later, while hunting, he accidentally slew his father; and, expelled from Italy on account of this involuntary crime, he began his wanderings.
In the course of time Brutus went to Greece, where he found the descendants of Helenus, one of Priam's sons, languishing in captivity.

Brutus headed the revolted Trojans, and after helping them to defeat Pandrasus, King of Greece, obtained their freedom, and invited them to accompany him to some distant land, where they could found a new kingdom.
Led by Brutus, who in the mean while had married the daughter of Pandrasus, the Trojans sailed away, and, landing on the deserted island of Leogecia, visited the temple of Diana, and questioned her statue, which gave the following oracle: "'Brutus! there lies beyond the Gallic bounds An island which the western sea surrounds, By giants once possessed; now few remain To bar thy entrance, or obstruct thy reign.
To reach that happy shore thy sails employ; There fate decrees to raise a second Troy, And found an empire in thy royal line, Which time shall ne'er destroy, nor bounds confine.'" GEOFFREY OF MONMOUTH (Giles's tr.).
Thus directed by miracle, Brutus sailed on, meeting with many adventures, and landed twice on the coast of Africa.