A quatrain is a verse with four lines, or even a full poem containing four lines, having an independent and separate theme. Often one line consists of alternating rhyme,
existing in a variety of forms. We can trace back quatrains in poetic
traditions of various ancient civilizations, such as China, Ancient
Rome, and Ancient Greece; and they continue to appear in the
twenty-first century.
Haven't read the book but this may be helpful to you:
"<span>In The History of the Kings of Britain, Geoffrey of Monmouth proposes to set forth the history of the British kings starting with Brutus and ending with Cadwallo. Geoffrey undertakes this endeavor at the request of the Archdeacon of Oxford who presents Geoffry with an ancient text to translate from British into Latin. The history of the British kings shows how fortune, jealousy, and betrayal can lead to the demise of an entire nation. On the other hand the text also details the qualities that are necessary in a good ruler who unites his people in peace. While Geoffrey's account reads like a novel, the basis for the book is historical and gives the reader a generalized view of British history."
source: </span>http://www.bookrags.com/studyguide-the-history-of-the-kings-of-britain/#gsc.tab=0
Soldier battle is the answer that I think it is
