 Some historians, such as Ernst Nolte, have considered that Adolf Hitler and Joseph Stalin used the Spanish Civil war as a testing ground for modern warfare, and that the Spanish Civil War, along with World War II, to be part of a European Civil War which lasted from 1936 to 1945 and was mainly characterised as a left/right ideological conflict.This interpretation has not been accepted by most historians, who consider the Spanish Civil War and the Second World War to be two distinct conflicts.Among other things, they point to the political heterogeneity on both sides ("See Spanish Civil War