Pope Francis has developed pneumonia in both lungs as he remained hospitalized Tuesday in Rome, according to the Vatican, which called the 88-year-old's condition "complex."

Pope Francis has spent a peaceful night at Rome’s Gemelli hospital and continues his recovery today, Vatican spokesman Matteo Bruni tells journalists at the Holy See Press Office.

Pope Francis has been in and out of the hospital several times over the past few years, previously undergoing abdominal surgery and receiving treatment for bronchitis, a hernia, and more.