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.
Historians use a wide variety of sources to answer questions about the past. In their research, history scholars use both primary sources and secondary sources. Primary sources are actual records that have survived from the past, such as letters, photographs, articles of clothing. Secondary sources are accounts of the past created by people writing about events sometime after they happened.