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

Pope Francis was in critical condition Saturday after he suffered a long asthmatic respiratory crisis that required high flows of oxygen, the Vatican said.

Thousands of people gathered in St. Peter’s Square to pray for an ailing Pope Francis, expressing sorrow for his suffering, hope for his recovery and gratitude for his efforts to steer the Catholic Church in new directions.