The Grindelwald Revolution was a period of history conflict that turned Europe upside down, with foundations being laid decades before hostilities broke out. It was initiated by the Dark Wizard Gellert Grindelwald, who aimed to unite Magical Europe under a single government, tear down the International Statute of Secrecy and reform the International Confederation of Wizards into a hierarchical new world order that would subjugate Muggles under the wise and powerful rule of Wizardkind.
The conflict began with the bombing of the Danish Ministry of Magic in 1910 and ended with Grindelwald's defeat in a duel against his arch-nemesis Albus Dumbledore in 1945.
Effects in the Muggle World
While Grindelwald was slowly implementing his plans in Wizarding Europe, he made plans to ease his eventual conquering of the Muggle world. A German, Adolf Hitler, was Grindelwald's alpha pawn. Under a powerful Imperious spell, Hitler rose to the top of the German political scene, becoming the country's leader in 1933 as part of the Nazi Party, whose radical policies were put in place by Grindelwald himself. The Imperioused Hitler rearmed the country and planned a war that would unite Muggle Europe under his rule, mirroring Grindelwald's plan for Magical Europe. In addition to Hitler, Mussolini, although not Imperioused, was threatened into submission by Grindelwald himself, forcing him to ally with Hitler in the war, despite Italy not being in the state to effectively fight a world war.
When Magical Europe descended into total war in 1939, Muggle Europe faced a similar situation. The day Grindelwald's Army marched on France's parliament, Muggle Germany invaded Poland, quickly crushing the small nation. During the final days of the war, it was clear that both Hitler and Grindelwald were losing their respective wars. After Grindelwald's defeat at the hands of Albus Dumbledore, the Imperious curse affecting the German dictator wore off. Now aware of his actions and crimes he had committed, Hitler was beyond sickened and could not live with himself, leading him to commit suicide the same day.