The 84-year-old pope stood on the balcony of his suite on the 10th floor of the Gemelli Hospital for about 10 minutes, reading from a prepared text but also adding many impromptu remarks.
He appeared to be slightly short of breath at times. He had part of one of his lungs removed when he was a young man in his native Argentina.
Hundreds of people gathered in the open space below shouted "Viva il Papa!" (Long Live the Pope) and doctors and patients stood on other balconies to watch.
Several children who are patients in the hospital appeared with the pope on the balcony.
It was the first time since his election as pope in 2013 that Francis has not read the Sunday prayer and message from a window overlooking St. Peter's Square, expect for when he was traveling.
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