After hearing the NSDAP leader Hitler speak for the first time in 1920 at a Munich rally, Hess became completely devoted to him. They held a shared belief in the stab-in-the-back myth, the notion that Germany's loss in World War I was caused by a conspiracy of Jews and Bolsheviks rather than a military defeat.[23][15] Hess joined the NSDAP on 1 July as member number 16.[24] As the party continued to grow, holding rallies and meetings in ever larger beer halls in Munich, he focused his attention on fundraising and organisational activities.