The book "Sources of German History in the Middle Ages to the Mid-Thirteenth Century, Volume One (of Two)" by Wilhelm Wattenbach is an important source for the study of the history of medieval Germany. This book examines historical documents that shed light on the ancient history of the country during the first half of the thirteenth century. The author has analyzed in detail various sources, including chronicles, correspondence and other documents, which allows the reader to better understand the complex processes that took place during this period. This book is a must for those interested in the ancient history of Germany and who want to gain in-depth knowledge of this period.