A variety of cultures influenced the literature of the High Middle Ages, one of the strongest among them being Christianity. The connection to Christianity was greatest in Latin literature, which influenced the vernacular languages in the literary cycle of the Matter of Rome. Other literary cycles, or interrelated groups of stories, included the Matter of France (stories about Charlemagne and his court), the Acritic songs dealing with the chivalry of Byzantium's frontiersmen, and perhaps the best known cycle, the Matter of Britain, which featured tales about King Arthur, his court, and related stories from Brittany, Cornwall, Wales and Ireland. An anonymous German poet tried to bring the Germanic myths from the Migration Period to the level of the French and British epics, producing the Nibelungenlied. There was also a quantity of poetry and historical writings which were written during this period, such as "Historia Regum Britanniae" by Geoffrey of Monmouth.