"Once upon a time" is a stock phrase that has been use in some form since at least 1380 (according to the Oxford English Dictionary) in storytelling in the English language, and seems to have become a widely accepted convention for opening oral narratives by around 1600. These stories often then end with "... and they all lived happily ever after", or, originally, "happily until their deaths." These are examples of the narrative form, and occur most frequently in the narratives produced by children aged between 6 and 8.