Majority rules?
Numerous sources on the web tell us that the correct date is May 31, 1884. Of course most of these "numerous sources" simply copy from others, such that finding the original source (there probably is such a thing) is close to impossible. So did this really happen in 1884? A page on How Breakfast Foods Were Invented which is part of the larger Kellogg's web site tells us that:
As early as 1894, the Kellogg brothers were determined to develop a tasty, nutritious breakfast food that people would enjoy eating.
which suggests that maybe somebody copied the year wrong, and since then everybody has been copying from that source. On the other hand, the Kellogg company was run by Will, who apparently didn't get along well with his brother John. Will was the businessman, John the doctor, and inventor. Maybe Kellogg's doesn't want us to know that John had developed a product well before Will started working with John. I'm not much for family intrigue, but it's a possibility.
The patent office undoubtedly has records which can be checked, but I'm not going to devote my time to that task. I'll simply go along with the majority.
Go to: A flakey accident?, or
Go to: How Deep is My Linking?