The Treaty of Versailles in the mind of the Germans stabbed them in the back, especially the guilt clause that made them take blame for the First World War. Hitler capaitalized on these sentiments and used them to rally the German people.
Primary sources are the first hand evidence left behind by participants or observers at the time of events. Primary sources originate in the time period that historians are studying. They vary a great deal.
Primary, secondary and tertiary sources are broadly defined here as follows: Primary sources are sources very close to the origin of a particular topic or event. An eyewitness account of a traffic accident is an example of a primary source.