VATICAN CITY (CNS) -- As Pope Francis prepared to spend the 12th anniversary of his election at Rome's Gemelli hospital, people at the Vatican and around the world were responding to his most frequent personal request.

"From the beginning of his pontificate, we have heard Pope Francis ask us to not forget to pray for him, and that is what we are doing," said Cardinal José Tolentino de Mendonça, prefect of the Dicastery for Culture and Education, as he led thousands of people praying the rosary for the pope March 10 in St. Peter's Square.

"It is not only Christians who are doing so, but the faithful of other religions and even many nonbelievers also are joining their hearts around Pope Francis," the cardinal said.

Pope Francis has made requesting prayers a hallmark of his papacy and a standard way to end a letter or speech.

When the 76-year-old Cardinal Jorge Mario Bergoglio of Buenos Aires, Argentina, was elected to succeed Pope Benedict XVI March 13, 2013, and came out onto the balcony of St. Peter's Basilica, his words stunned the crowd:

"Before the bishop blesses his people, I ask you to pray to the Lord that he will bless me -- the prayer of the people asking a blessing for their bishop. Let us make, in silence, this prayer: your prayer over me," he said, and bowed to receive the blessing.

And again, before he said good night, he told the crowd, "Pray for me."

Probably not a day has gone by since then that he hasn't made the request out loud or in writing.

Four months after his election, on his flight back from Rio de Janeiro, Brazil, a journalist asked him why he always asked for people's prayers. "It isn't normal, we are not used to hearing a pope ask so often that people pray for him," the reporter said.

"I have always asked this," the pope responded. "When I was a priest, I asked, but less frequently. I began to ask more often when I was working as a bishop, because I sense that if the Lord does not help in this work of assisting the people of God to go forward, it can't be done."

"I am truly conscious of my many limitations, of many problems, of also being a sinner -- as you know! -- and I have to ask for this," he said. "It is a habit, but a habit that comes from my heart."

Pope Francis also often thanks people for their prayers.

"I would like to thank you for the prayers, which rise up to the Lord from the hearts of so many faithful from many parts of the world," the pope wrote in his text for the Angelus prayer March 2. "I feel all your affection and closeness, and, at this particular time, I feel as if I am 'carried' and supported by all God's people. Thank you all!"

And while no photos of the pope have been released since he entered the hospital, his labored voice was broadcast in St. Peter's Square March 6 in an audio message thanking the gathered faithful for their prayers.

Hospitalized since Feb. 14 with bronchitis and difficulty breathing, Pope Francis was later diagnosed with double pneumonia. His doctors told reporters he has chronic lung conditions: bronchiectasis and asthmatic bronchitis, caused by years of respiratory problems and repeated bouts of bronchitis.

In his autobiography, Pope Francis wrote about the surgery he underwent at the age of 20 to remove the upper lobe of his right lung after suffering a severe respiratory infection.

"It was extremely painful. Extremely," he said.

When writing or talking about the pope's lung surgery, people often mistakenly assume doctors had removed the entire right lung. It even was an issue at the 2013 conclave that elected him.

During the lunch break between the third and fourth ballots of the conclave, he wrote in the autobiography, a group of European cardinals invited him to sit with them. They began asking so many questions on so many topics "that I found myself thinking: Hah, it seems like an exam."

At the end of the meal, he said, a Spanish-speaking cardinal asked him, "Do you have a lung missing?"

After explaining that only the upper lobe had been cut away in 1957, Pope Francis recalled that "the cardinal turned red, uttered a swear word and clenched his teeth: 'These last-minute maneuvers!' he exclaimed."

"It was then that I began to understand" he was being seriously considered as a candidate to succeed Pope Benedict. It happened that evening with the conclave's fifth ballot.

The Catholic Church in Pope Francis' native Argentina planned to celebrate the pope's 12th anniversary March 13 with special Masses in every diocese.

Archbishop Marcelo Colombo of Mendoza, president of the Argentine bishops' conference, said the Masses, in addition to offering prayers for the pope's continued recovery, would be a "public witness of our gratitude for his generous dedication, which has borne abundant fruits of pastoral love over the years."