These inventions are varied and many, such as the introduction of written language, the invention of recycleable typefaces, the invention of stave notation for chanting, and so on.
However, one of my favourites is the invention of propaganda. More precisely, the Congregatio de propaganda fide, which was a committee of cardinals at Rome established in 1622 for propagating the Faith throughout the world.
Who would have thought that such a useful political tool could come from what I previously thought were unthinking slaves? Clearly, I was mistaken. I doff my virtual cap at The Church today, and look forward to learning more about it.