This book was great because it was a great lead and the book was credible because a renowned Persian historian wrote it in the 11th century.Kelly, Eirc P. The Trumpeter of Krakow. New York: The Macmillan Company, 1928. This book was a primary source because it included first-hand accounts of trumpet playing instituted in the times of the Mongols. Although this book contains no accounts of the time when the Mongols first initiated it, it nevertheless provides a great history about the tradition. Again, this book wasn't really biased towards one side, but it was a credible source because it was written by one of the trumpeters himself. May, Timothy. Mongol conquests in world history. UK: Reaktion Books, 2013. This book was very helpful when writing the article as it provided excellent first-hand accounts of the Mongol invasions of Hungary and the positive impact left by the Mongols . Additionally, the book also had excellent background research, which helped me in the reference section of my paper. However, this had an obvious bias against the Mongols as it repeatedly mentioned the carnage of the Mongols without mentioning the