In 1988, Jan Peters discovered a diary-like manuscript of a mercenary from the Thirty Years' War. Over 24 years, this individual traveled 22,400 kilometers across Europe. However, he revealed nothing about his name, age, or origin. Researching his life is challenging: much of what is of interest today was never recorded, and much has been lost. Only a document from Mühlhausen in Thuringia definitively clarifies the name of the mercenary: Peter Hagendorf. This volume contains the complete text of the diary. Observations about the writer's life paths, lifestyle, and values place his life within the events of the time and provide access to the everyday world of the mercenary. Peter Hagendorf describes his tumultuous military and family life in a sober yet touching manner. It is an exciting and authentic life account, and a unique one at that.