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.

The pontiff’s death initiated a well-structured series of rituals designed to mourn the loss of the 1.3 billion-member church’s leader and to ensure stability with the selection of a new pope.

Tributes to Pope Francis poured in from around the world on Monday after the Vatican announced the pontiff's death at age 88. The 266th pope was praised for his groundbreaking steps to honor the poor and the vulnerable;