What did I do to get such a noble person to follow me?
So sense FIM Earth is not like real Earth, I came up with its own history. Let's begin.
So in FIM Earth, Evolution is slightly different and Humans not only come from Ape's but Horses too. The first Human was a Centaur. You see, Celestia accidentally a Horse and Ape and created a Horse Ape. To avoid disaster, she created the Centaur. Then they evolved in Humans. This is also why everyone's blue.