Aesop was a Greek fable writer and storyteller believed to have lived in the 6th century BC. His fables, short stories that often feature animals as characters and contain a moral lesson, have been passed down through the ages. Some of Aesop's most well-known fables include "The Tortoise and the Hare," "The Wolf in Sheep's Clothing," and "The Boy Who Cried, Wolf." These and many other fables by Aesop are still popular today and are often used to teach moral lessons to children.