The Sino-Soviet Treaty of Friendship, Alliance, and Mutual Assistance was a 1950 agreement between China and the Soviet Union that formalized their alliance following the establishment of the People's Republic of China. The treaty aimed to solidify their political, military, and economic ties, promoting mutual defense and support against imperialist threats. This partnership played a critical role in shaping Sino-Soviet relations and is essential to understanding the causes and effects of the subsequent Sino-Soviet Split.