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.

The Golden Ass
or The Metamorphosis
by Apuleius

The ancients had novels (who knew?!), and this is one of them.  And, believe it or not, it's a fun read, lighthearted, funny, and well written. The story moves.  For the boys: it even has explicit sex. Amazing.  Who knew?!

The story is about Lucius' adventures after he gets turned into a donkey.  The first ten chapters are just fun, not related to the Pagan origins.

Chapter eleven is about Lucius in Egypt, and his study and initiation into the mysteries of Isis and Osiris (he's a man again by this point).  For the ancients these mysteries were sacred secrets -- believers would die rather than reveal them.  Apuleius' novel is the only surviving text that comes close to describing the mystery initiation ceremony.  Apuleius also says initiation brought salvation:

"The keys of hell and the guarantee of salvation were in the hands of the goddess, and the initiation ceremony itself a kind of voluntary death and salvation through divine grace."

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