Simplify the following text for a Grade 8 native English-speaking person.
Original: Scholars speculate that `` there probably existed in the fifth century ( BC ) a written book containing various fables of Aesop , set in a biographical framework . '' We do not know who authored such a book or what it said about Aesop , but by the time of Classical Greece Aesop and the fables attributed to him seem to have been widely known .
Simplified: Aesop 's Fables or Aesopica refers to a collection of fables credited to Aesop .