Some doof on the internet tells you the central figure of western civilization is a Pagan myth, and you're going to take my word for it?  What, are you nuts?

Of course not.  You're not going to believe me, and you're not going to believe any agenda driven modern scholars. You're going to discover the facts for yourself, directly from the pens of the ancients.  Here's an important ancient sourcebook.

Isis and Osiris in Moralia V
Loeb Classical Library #306
by Plutarch

This is the same Plutarch who wrote Plutarch's Lives.  Like Solon, Plato and Pythagoras before him, when he wasn't biographying Plutarch traveled to Egypt and studied the mysteries of Isis and Osiris -- probably even got initiated (though he doesn't say for sure).

Isis and Osiris, at just over 90 pages, is modern scholarships main source for the goodies on one of the ancient world's big name Pagan religions. 

This Loeb translation is pretty easy to read. And fun. You'll discover "accounts of the dismemberment of Osiris and his revivification and regenesis" [Isis and Osiris, 365] -- His death and resurrection!  

Wow.

Be careful, there are a bunch of P's Moralias in print at Loeb and elsewhere. For Isis and Osiris, you want number V, which is Loeb #306.

And the good thing is, you don't have to believe me, you can read it for yourself. Available at amazon.com