In Chapter Two of Animal Farm, the animals have their much-anticipated Rebellion in which Mr Jones is overthrown and they take possession of the farm. It was Old Major's rousing speech (in Chapter One) that inspired this revolt and whose ideas were developed (by the pigs) into a "complete system of thought" called Animalism.

In accordance with Old Major's ideas, Animalism emphasises the equality of all animals and portrays Man as their greatest enemy. Once Man (Mr Jones) has been overthrown, the animals change the name of Manor Farm to Animal Farm and condense the principles of Animalism into Seven Commandments. These commandments are then inscribed onto the wall of the barn and form the basic tenets of everyday life.

Over time, however, these principles are manipulated by the pigs and used against the other animals to create an environment of oppression and control, making life under Mr Jones seem far more idyllic than it really ever was.