The event was significant not only for Yugoslavia and <answer>Tito</answer>, but also for the global development of socialism, since it was the first major split between Communist states, casting doubt on Comintern's claims for socialism to be a unified force that would eventually control the whole world, as <answer>Tito</answer> became the first (and the only successful) socialist leader to defy Stalin's leadership in the COMINFORM. This rift with the Soviet Union brought <answer>Tito</answer> much international recognition, but also triggered a period of instability often referred to as the Informbiro period. <answer>Tito</answer>'s form of communism was labeled "<answer>Tito</answer>ism" by Moscow, which encouraged purges against suspected "<answer>Tito</answer>ites'" throughout the Eastern bloc.
Who became the first leader to defy Stalin's leadership?
Tito