Also included were epistles, gospels, acts, apocalypses, homilies, and collections of teachings. The Bamberg Apocalypse belongs in the category of Ottonian Apocalypses. At the core, apocalypses are a form of theodicy. He then began the process of writing several "Apocalypses", a term which means "revealing". It deals with the End of the World, each issue dealing with differently themed Apocalypses. A large part of this "secret" literature was the apocalypses.