From 1933, Hungarian foreign policy closely collaborated with Nazi Germany in the hope of revising the borders that had been established by the 1920 Treaty of Trianon. In March 1933, the Hungarian prime minister declared that Hungary "requests justice in the historical principle" and wanted the redeem of Hungarian-inhabited territories that had been lost after World War I. In June 1933, Hungarian Prime Minister Gyula Gömbös visited Germany and, together with Adolf Hitler, concluded that Czechoslovakia was the main obstacle for "rearrangement" of Central Europe and that Czechoslovakia should be disintegrated from within, internationally isolated and then eliminated by military power. During a meeting with Hitler in August 1936, Miklós Horthy explained the purpose of a common attack against Czechoslovakia as removing a "cancer tumor from the heart of Europe". At the end of 1937, Hitler decided to start action against Czechoslovakia. In 1938, Germany and Hungary focused on creation of a common platform against Czechoslovakia, and in November, Hitler negotiated with the Hungarian government and on the destiny of Czechoslovakia.