In "Animal Farm," after Snowball's expulsion, what is foreshadowed when the animals learn that Snowball's heroism was "much exaggerated"?

The animals saw Snowball's heroism for themselves. However, after Snowball is expelled, Squealer tries to tell them that Snowball was really not a hero afterall. This foreshadows the rewriting of other history that will take place during the rest of the story. It also foreshadows the rewriting of the original commandments given written by Snowball and Napoleon. Once Snowball is gone, Napoleon is free to rewrite both the commandments and history according to his point of view. This parallels the rewriting of history that took place during the rule of Stalin in the Soviet Union.