Old Major, the elder pig in Animal Farm, seems to have a different role than the younger ones. I believe he has a different view, but after he dies, the young pigs don't follow his legacy.
What does that mean?
I've always thought of Old Major as representing Vladimir Lenin. Old Major is the figure with the vision and ideology who inspires the other animals and kicks off the revolution, then dies and leaves the actual shaping of the new state to his successors, Snowball and Napoleon, who vie for control. This parallels Lenin's death leaving control of the Soviet Union to his two successors, Trotsky and Stalin, both of whom claimed to be the true heir of Lenin.
Snowball, who comes up with a plan to build a windmill and then is exiled from the farm by Napoleon, represents the more intellectual Leon Trotsky, while Napoleon, who creates a police state, exiles Snowball, consolidates power in the hands of the pigs, and corrupts the original philosophy by working with humans, represents the militaristic and anti-intellectual Joseph Stalin.
The parallel is not exact, as Lenin lived long enough to carry out his revolution and spend a brief time ruling the Soviet Union, whereas Old Major dies before the revolution starts.