A few days later Tito arrived and Maclean had to convey Churchill 's displeasure at his sudden and unexplained departure . Tito had been to Moscow at Stalin 's invitation , to arrange matters with the Soviet High Command . Maclean helped to hammer out a draft agreement , and went to London with it , while Tito 's envoys took it to Moscow . " It was a difficult and thankless task . King Peter , quite naturally , was not easy to reassure , and Tito , sitting in Belgrade with all the cards in his hand , was not easy to satisfy . " The bargaining went on for months , and meanwhile Maclean 's staff wanted to get away , to assist guerrilla wars elsewhere . When the Big Three ( Churchill , Roosevelt , and Stalin ) met at Yalta in February 1945 , and made it clear that Tito and Šubašić had to get on with it , King Peter gave in , and all the pieces fell into place . The regents were sworn in , as was the united government , and the British ambassador flew in . Maclean was finally able to leave
met at Yalta
Yalta Conference
Eastern Approaches