LAZIO, Rome — Pope Francis yesterday marked 12 years 'on-the-job' job as leader of the Catholic Church—with a cake—at the Fondazione Policlinico Universitario Agostino Gemelli (Gemelli University Hospital in Rome's Lazio district, slowly recovering after a month in the hospital but with his health casting a shadow over his future.

The 88-year-old Argentine pontiff was for a time critically ill, battling pneumonia in both lungs. His situation has markedly improved since he was hospitalized on Valentine's Day, February 14. Reports from the Vatican said he is in 'stable' condition at least well enough to eat his cake.

"He celebrated a little bit with the health workers who have been helping him during this time with a cake and candles," the Vatican press office said late Thursday.

Francis spent the morning following prayers and meditations in the Vatican via videolink, without being seen, alongside his usual treatments and physiotherapy, the Holy See said. After that, he prayed and continued his breathing exercises.

Other than his cake, no special events were planned for his anniversary, but the Vatican said he was shown hundreds of messages of goodwill sent from schools, religious institutions and young people.

Talk is now turning to when he might go home. But his hospital stay—the longest and most fraught of his papacy—has raised doubts about his ability to lead the world's nearly 1.4 billion Catholics.

"It takes time for a body of 88 years old affected by bilateral pneumonia to recover, also in terms of energy, of strength," the press office cited.