Concerns over Pope Francis' health have mounted in recent years as have questions about his succession. Here's what we know.

As Pope Francis fights double pneumonia in hospital, millions are praying for the leader of the Catholic church to make a full recovery. However, should the worst happen, the centuries-old process of selecting a new Pope,

Pope Francis, battling double pneumonia, remains in a critical condition and his prognosis is still guarded because of the "complexity" of his clinical condition, the Vatican said on Sunday. The pope was admitted to Rome's Gemelli hospital on February 14 after having trouble breathing for several days and subsequently had pneumonia diagnosed in both lungs.