dr.frankenstine
The most popular fairy tale book from "Once Upon a Time" is "Grimm's Fairy Tales."
"Once upon a time..."
the usual opening line of fairy tales is the "once upon a time"
Once upon a time.....
fairy tales do
Igor
It usually begins with "Once upon a time,".
A Fairy Tale.
Once upon a time or a long time ago.
Most fairly tales begin with the four words once upon a time. Fairy tales have existed for centuries and usually have a moral to share.
There was no stated information on that topic
This is likely the term "once upon a time" that introduces fairy tales.