Geoffrey of Monmouth was a British cleric and historian who lived in the 12th century. He is most well-known for his work, Historia Regum Britanniae, a chronicle of British history from its mythical beginnings to the 12th century. Synonyms for Geoffrey of Monmouth might include historian, chronicler, writer, scholar, or cleric. His work also falls into the category of medieval literature, British history, or Arthurian legend. Geoffrey's name and legacy have become synonymous with his historical accounts of British monarchs and his role in shaping the mythology of King Arthur and the Knights of the Round Table.