History of the Britons (Historia Brittonum) by Nennius. The Historia Brittonum describes the supposed settlement of Britain by Trojan expatriates and states that Britain took its name after Brutus, a descendant of Aeneas. The work was the "single most important source used by Geoffrey of Monmouth in creating his Historia Regum Britanniae" and via the enormous popularity of the latter work, this version of the earlier history of Britain, including...