India, April 22 -- Pope Francis died of a stroke, causing a coma and "irreversible" heart failure, according to his death certificate released by the Vatican Monday. He had been battling double pneumonia since earlier this year and had been staying at Rome's Gemelli Hospital. Here's all you need to know about the life-threatening illness he battled with.

Pope Francis, the 88-year-old Catholic leader, died on Monday morning, almost a month after being discharged from five weeks in hospital with double pneumonia.

In an interview with HT Lifestyle earlier this year in February, Dr Caroline Simon, consultant pulmonologist at Wockhardt Hospitals in Mumbai's Mira Road, explained, "Double pneumonia is a life-threatening lung infection that tak...