This book describes how the Renaissance understanding of ancient Britain remained affected by medieval conceptions which forces such as humanism and antiquarianism by then should have rendered obsolete. The reason for this remaining medievalism was that the tradition based on Geoffrey of Monmouth became so relevant to Protestant patriotism that a great many Protestant English writers clung to it or were influenced by it despite its evident historical inaccuracies. This study charts this trend by examining each of the phases of Geoffrey's anti-Roman narrative and how English writers appropriated them: the pure and model primitive British church, the nation's Trojan origin, the ancient British laws and Britain's sack of Rome, the resistance to Caesar's invasion, the continued resistance to the Romans in the first century, and finally the Arthurian victories over Rome. Drayton, Spenser, Shakespeare, and Milton figure prominently, but a wide range of authors is considered, both poets and non-poets.