What's the history behind the terminology ' cats have nine lives'?

Answer 1

From The alt.usage.english :

"Given to a cat. How a cat got to have nine lives lies somewhere in the murk of the dark ages. Shakespeare's character Tybalt (Romeo and Juliet) was a reference to a cat and hence Mercutio's ill fated, "…nothing but one of your nine lives…"."

Also, for Etymology OnLine:

"Cats were domestic in Egypt from c.2000 B.C.E., but not a familiar household animal to classical Greeks and Romans. The nine lives have been proverbial since at least c.1562."

And, again, from Answer Bag:

"Ancient mathematical philosophers called "nine" the "finishing post" and "that which brings completion." This is when the luck of the cat runs out, when he/she has used up their nine lives. All of this comes from ancient belief systems and superstition. The word nine is still very popular today."

Hope that does it for you!

Answer 2

It was developed by the people that wanted a good name for their Cat Food.