Pope transformed the church’s senior leadership, exposing growing differences over teachings. “Once you start opening the door, then there is confusion and also ambiguity in the doctrines,” says one cardinal.

Before mourners in their thousands gather in St. Peter’s Square to grieve, before leaders from around the world arrive to pay their respects, and long before cardinals cloister themselves to consider the future, the Vatican holds a small ceremony when a pope dies.

Although Pope Francis simplified the papal funeral rites in a move of typical modesty, Saturday’s ceremony will still be full of pomp and pageantry, as the world’s Catholics bid him farewell and cardinals in the Vatican ready themselves for the millennia-old process of picking a new pontiff.