It was in the post-World War I period that the Austrian-born Adolf Hitler, under the influence of the stab-in-the-back myth, first took up German nationalist ideas in his "Mein Kampf". Hitler met Heinrich Class in 1918, and Class provided Hitler with support for the 1923 Beer Hall Putsch. Hitler and his National Socialist friends shared most of the basic pan-German visions with the Pan-German League, but differences in political style led the two groups to open rivalry. The German Workers Party of Bohemia cut its ties to the pan-German movement, which was seen as being too dominated by the upper classes, and joined forces with the German Workers Party led by Anton Drexler, which later became the National Socialist German Workers Party (Nazi party) that was to be headed by Adolf Hitler from 1921.