Napoleon, like many historical dictators, makes great use of propaganda to establish his "reign." He rewrites history when he changes the commandments; more subtly, he recreates the character of Jones for the younger animals, and threatens them with Jones' return if they don't support him. How bad would this have been? Isn't Napoleon just Jones with two more legs, a little more weight, and an uglier face (unless you're a female pig :))? He has the dogs (his secret police) to control the animals, but he knows that it would be better if he could win their hearts and minds, even as he uses force to terrorize them.
This manipulation of the past, actually re-creation or simply creating of the past, is key to controling the people. In 1984, it becomes the famous formula: "Who controls the present controls the past; who controls the past controls the future." Imagine, not only controlling and oppressing the people, but having them love you for it!
Napoleon, one of two pigs who takes pre-eminent lead in Animal Farm, shows true dictator skills over his rival, Snowball. Very early in the story, Napoleon takes charge of Bluebell's puppies and decides to be in charge of their raising. It is not until Snowball's expulsion from the farm that we learn that Napoleon has actually assembled an army by making the now grown young dogs his military force. Dictators, such as Fidel Castro, the late Saddam Hussein, and North Korea's Kim Jong Il, often appear in military uniforms as the military is the source of their power.
He also awards himself several military honors and begins to re-write history by have his propoganda minister, Squealer, tell different official versions of Snowball's role on Animal Farm. Numerous other examples exist throughout the book including the displaying of his own likeness and the re-writing of the Seven Commandments.
The name Napoleon is perfect for the pig who became ruler of Animal Farm. He probably had that name from Jones because he had a Napoleonic character, i.e., he acted like the boss pig. Napoleon Bonaparte did not take part in the beginning stages of the French Revolution, but he assumed leadership of the revolution after the King had been overthrown and a democratic government established. Then Napoleon Bonaparte used military force and the ideals of the revolution to establish himself as Emperor and to appoint some of his relatives as kings. Napoleon the pig behaves in a similar manner. He appropriates the animal revolution for his personal aggrandizement and material gain. Orwell's implication is that getting rid of a king can result in getting an emperor. In Aesop's fable about the frogs who wanted a king, the frogs got rid of King Log and ended up with King Stork who devoured all of them.