Francis, who lost part of a lung to a respiratory infection in his youth and has been plagued by ailing health recently, last year approved a stripped-down funeral for himself, eschewing some of the more arcane rites and rituals that take place when a pope passes away.

Pope Francis has been known for his down-to-earth leadership, support of marginalized communities and interreligious dialogue.

Explore the fascinating history of how the papal conclave works, and learn about some of the cardinals who could succeed Pope Francis.

The pope is susceptible to lung infections after he developed pleurisy as an adult and had part of a lung removed at age 21. In addition, Francis has been hospitalized for bronchitis multiple times, and in 2023 underwent abdominal surgery and received treatment for pneumonia earlier that year.

Vatican officials cleared his schedule through the weekend due a “complex” infection plaguing the 88-year-old pontiff.

Pope Francis, who remains hospitalized, has bilateral pneumonia, the Vatican said on Tuesday. The term simply means pneumonia in both lungs, said Dr. James Musser, director of the center for infectious diseases at the Houston Methodist Research Institute.

The Vatican said in a statement on Tuesday (February 18) that Pope Francis has the onset of "bilateral pneumonia," complicating treatment for the 88-year-old pontiff and indicating a further deterioration in his fragile health.