Three years of mounting international tension - encompassing the Spanish Civil War, the Anschluss (union) of Germany and Austria, Hitler's occupation of the Sudetenland and the invasion of Czechoslovakia - culminated in the German invasion of Poland on 1 September.
Three years of mounting international tension - encompassing the Spanish Civil War, the Anschluss (union) of Germany and Austria, Hitler's occupation of the Sudetenland and the invasion of Czechoslovakia - culminated in the German invasion of Poland on 1 September. Britain and France declared war on Germany two days later. While the USA proclaimed neutrality, it continued to supply Britain with essential supplies, and the critical Battle of the Atlantic between German U-Boats and British naval convoys commenced.