Medieval Plays

When I think of Carnival season, I think of New Orleans and Rio. What I did not know is that Carnival is celebrated all over the world, especially in Europe. I was looking through an album of Carnival posted on usatoday in hopes of finding some cool Mardi Gras pictures from New Orleans. None existed. The album was from all the parades in Rio and across Europe, and these pictures from Europe reminded me of all the "parades" from medieval theatre.
I was also interested in how influencial the church was to theatre. The fact that the church essentially forced theatre out of existence and then brought it back in order to bring more people to the church is somewhat ironic. I would like to know at which point theatre became completely separate from the church, but my guess would be that it was as soon as theatre became a business. Additionally, the parade plays were all biblical stories that most everyone could relate to. I also think that as relgions diversified and people became less familiar with the bible, theatre began transitioning into a business.