Turned out to be Aesop's Fables.
There are many uncertainties in this world but I feel confident in saying that Aesop was not a Christian. Since he lived about 600 years before Christ was born.
Still a good book and one that I consider a foundational work for civilization.
Well, there were Christians before Christ was born, if you count the Old Testament Prophets! But yeah, I get your point. There were quite a few philosophers who were very moralistic in their teachings.
I always liked Aesop’s Fables!