A Connecticut Yankee in King Arthur's Court/WMG

The Catholic Church infiltrated Morgan's Education Department.
Despite the part where Clarence says education cannot cure superstition, education is one of the most powerful forces in the world. And the Catholic Church, since it ruled for so long, surely would have known that. If Morgan's education would have been as he envisioned it, his pupils would not have deserted him, but it was hijacked from the start. The Church replaced the teachers. Hey, if they could replace the men on Hank's steamer, they could replace the teachers!

This book is about Nikola Tesla
Consider:
 * Nikola Tesla and Mark Twain were good friends
 * The premise of the story is a man who gets sent back in time with massive knowledge of future technology, and attempts to create as much of it as possible, but most people don't see any use in it aside from diversions and minor things. Many years later the general public begins to 'discover' these technologies, with little-no record of their past existence.
 * They were opposed by someone with little skill who mostly knew how to display.