Aesop's Fables or Aesopica refers to a collection of fables credited to Aesop (620–560 BC), a slave and story-teller who lived in Ancient Greece. Aesop's Fables have become a blanket term for collections of brief fables, usually involving personified animals. The fables remain a popular choice for moral education of children today. Many stories included in Aesop's Fables, such as The Fox and the Grapes (from which the idiom "sour grapes" was derived), The Tortoise and the Hare, The North Wind and the Sun and The Boy Who Cried Wolf, are well-known throughout the world.