This did not mean, however, granting the Chinese communists a free hand. After the establishment of the People’s Republic of China in October 1949, Mao went to Moscow to negotiate a new treaty of alliance. He arrived on 16 December and he did not return to Chinese soil until 27 February 1950. Over the two months of hard bargaining Stalin succeeded in holding on to most of the gains he had claimed at Yalta and in the 1945 treaty with the nationalist government. But he also had to accept the burden of agreeing to come to China’s assistance in the event of an attack by Japan ‘or any atate allied with her and thus being in a state of war’. The latter qualification was to prove its importance in the Korean War and other Sino-American military engagements. Stalin may have disappointed his new Chinese allies with the paltriness of his economic assistance, limited to the value of US$300 million spread over five years, but he pleased them with his secret military assistance.