Human fragility has the power to make us more lucid about what endures and what passes, what brings life and what kills,” Pope Francis wrote in a letter to the editor in chief of Corriere della Sera.

For the first time since Pope Francis was hospitalized in mid-February, the Vatican press office released a photograph of him March 16; the image shows him concelebrating Mass that morning in the chapel of his suite of rooms at Rome's Gemelli hospital.

Pope Francis acknowledged being fragile and "facing a period of trial" as he thanked well-wishers Sunday for prayers in a message from hospital.