When did Fidel Castro start his leadership in Cuba?

Fidel Castro began his leadership in Cuba after the success of the Cuban Revolution in January 1959. While he was involved in opposition activities as early as the mid-1950s, including the attack on the Moncada Barracks in 1953, his formal leadership as the Prime Minister of Cuba commenced after he and his revolutionary forces overthrew the Batista regime.

The year 1965, specified in the answer, is significant as it marks the time when Castro had consolidated power and was deeply involved in establishing a one-party socialist state, but it does not denote the beginning of his leadership. The correct year reflecting the start of his leadership is 1959, following the revolutionary victory.

This context illustrates an important timeline for understanding Castro's rise to power in Cuba and the considerable changes that took place during and immediately after this period, such as land reforms and social programs that were implemented. The wrong choices represent years that either were after his establishment of leadership or are outside the key events of the revolution itself.