Guess Who #26

Here are your clues:

I was an Augustinian monk.

I wrote one of the most published books of all time.

I was mistakenly buried alive.

(He was denied canonization as a saint because when his body was dug up splinters were found embedded under his fingernails.  The canonization authorities determined that a true saint wouldn’t fight death in such a manner.) 

Note: Evangelical Christians know that every born-again believer is a saint. We don't need to be "knighted by the proper authorities" to become a saint. We also don't pray to saints in Heaven. Saints alive! That's a small piece of why the Reformation was launched.)