Hundreds of cardinals attended mass inside St. Peter's Basilica at the Vatican Sunday, to mark the end of a nine-day mourning period for Pope Francis.

Following the death of Pope Francis, the Catholic Church has chosen a date to elect its new leader, in a process virtually unchanged in 800 years.The system is known as the ‘Papal Conclave,’ and is a democratic process with a strong emphasis on working through multiple rounds of voting until a clear consensus emerges.