Stalin's big starting point. Being one of Lenin's leadership contenders, he seemed to be least likely to succeed. He would form the triumvirate with Zinoviev and Kamenev.
May 1924, Lenin's testament isn't published
As General Secretary, Stalin replaces Leon Trotsky supporters.
1927, Crisis of the NEP (Grain Crisis)
Stalin made it appear as if he was a very close friend of Lenin's. He told Trotsky the wrong date of the funeral - he turned up a day late.
Stalin gets rid of Trotsky
Lenin's widow reveals his testament to the Central Committee. Zinoviev and Kamenev made sure that this was not published, helping Stalin's position.
This made Stalin compelled to become a leftist. Trotsky supporters join Stalin because of him being on the left side.
Slowly, Trotsky is becoming more and more isolated. When Stalin becomes party leader, Trotsky gradually got removed from his jobs. He was later sent to Siberia (1928) and then removed from the Soviet Union (1929). 1940, Trotsky is murdered by a Stalinist by driving an ice-axe into his skull.