The King completed his education at Cambridge University before being commissioned in the Royal Air Force. In mid-1941, the Yugoslav government-in-exile opened talks with the Greek government-in-exile for a post-war confederation––the Balkan Union––that would unite Yugoslavia, Greece and Bulgaria once King Boris III of Bulgaria was overthrown. The Greek prime minister Emmanouil Tsouderos supported the confederation plan, but objected to the Yugoslav plans to bring in Bulgaria and for the proposed confederation to have an executive government in charge of all economic, foreign policy and military questions, leading Tsouderous to ask the British Foreign Secretary Sir Anthony Eden to mediate. In July 1941, the Yugoslav government-in-exile recognized the Czechoslovak government-in-exile, and starting in September 1941 Peter regularly met with President Edvard Beneš to discuss a new Yugoslav-Czechoslovak alliance to replace the Little Entente that Beneš had negotiated with Peter's father, King Alexander, in 1921. On 31 December 1941, the Greek-Yugoslav talks concluded and on 15 January 1942 the "Accord entre le Royaume de Yougoslavie et le Royaume Grèce concernant la constitution de l'Union balkanique" was signed in London. The accord committed Yugoslavia and Greece after the war to have a common currency; a customs union; to co-ordinate their foreign policies; for a military alliance with joint staff talks for a common defense plan; and a committee consisting of the Yugoslav and Greek finance ministers, foreign ministers, and defense ministers to meet regularly to plan policies for the Balkan Union.