The Polish Invasion (also known as the September Campaign) was Adolf Hitler's first attack in World War II. It came after the lack of German support for Hitler's attempt to seek peace with Poland. He wanted peace because Poland received several former German provinces under the Treaty of Versailles after World War I. Britain nor France were prepared to fight against Nazi Germany, so they followed a law of peace. However, Germany had received part of Czechoslovakia's border, but none of the countries wanted to give it to them. Germany responded by disbanding the state of Czechoslovakia and creating a nonaggression pact with the Soviet Union (now know as Russia) called the German-Soviet Pact. They agreed by saying Poland would be divided between the two powers. As a result, Germany (and the Soviet Union) invaded Poland on September 1, 1939. The Polish army was defeated within weeks of the invasion.