Originally Posted by Baraka_Guru

Tell that to Winnie the Pooh author, A. A. Milne, who wrote a book entitled Once on a Time....

EDIT:
As an aside: language and how usage evolves is kinda funny. For example, we all know that (now cheap) phrasing used in mysteries and thrillers: "...when all of a sudden...."

What if I told you that older texts used something different? Try this on for size: "...when of a sudden...." The all crept in there and now all of us use and know it.