As Pope Francis has battled double pneumonia in hospital for nearly three weeks, talk of the 88-year-old pontiff's death or resignation has become almost commonplace.

The Vatican houses the central government of the Catholic Church and is also an independent city-state. The pope is both the head of the Catholic Church and head of state. In order to govern both, he has the Roman Curia, meaning “court.” In modern terms, the Curia is the papal bureaucracy. It is an extension of the pope’s authority.

Pope Francis suffered two new breathing attacks on Monday, requiring two separate bronchoscopies, the Vatican said, as the 88-year-old pontiff struggles to recover from pneumonia. “Today, the Holy Father experienced two episodes of acute respiratory failure,

The Vatican has laws to ensure the transfer of power when a pope dies or resigns, but they don't apply if he is sick.

Pope Benedict XVI officially stepped down as leader of the Roman Catholic Church, citing a "lack of strength of mind and body."

The Vatican has set in motion nightly prayers for Pope Francis in the hope that he might recover and get back to leading the Catholic Church.

When the Pope passes away, a complex and ancient process begins. Join us as we explore the intricate steps of papal succession, from the moment of death to the election of a new pontiff. Discover the fascinating traditions and rituals that have guided the Catholic Church for centuries.

Canon law states that a pope can resign, but it stipulates that the papal resignation must be “made freely and properly manifested”—conditions that would be difficult to ascertain if a pope were already incapacitated.

ROME (AP) — Pope Francis remained in critical but stable condition Tuesday, with his blood parameters remaining stable as he works from the hospital while battling double pneumonia, the Vatican said.

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