The Vatican also said Francis invited his household help to join him in a "family-like" atmosphere, and he spoke of them one by one during his homily.
Francis, who is making history as one of the more informal and down-to-earth popes in recent times, struck a modest note as he reflected out loud about people's roles in the world. "Let the Lord write our history," he said in his homily.
After Mass, all ate breakfast with Francis at the hotel's dining room.
Francis has already blown out the candles on his birthday cake, presented to him on Saturday by children at the Vatican, but another present awaits him. A delegation from his favorite Argentine soccer team, San Lorenzo, from his home team in Buenos Aires, will give him a replica of their championship trophy.
Vatican officials said no fixed time was set for the papal meeting with officials and at least one player from the team, an underdog which clinched the Argentine championship. The delegation flew from Argentina on Monday night on a private plane, to arrive in Rome on Tuesday.
"Arriving on such as special day, like the 77th birthday of the pope, this meeting seems made for God," said the team's vice president Marcelo Tinelli, shortly before departure.
The team delegation might be presented to Francis before or after Wednesday's public audience at the Vatican, although Vatican officials didn't rule out a possibility of a meeting sometime on the pope's birthday.
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