VATICAN CITY - Four homeless people, one of them carrying his dog, helped Pope Francis celebrate his 77th birthday at the Vatican on Tuesday.

They live on the street in the Rome neighborhood just outside the Vatican's walls and were invited by the Holy See official in charge of alms-giving to attend the morning Mass, which Francis celebrates daily at the hotel where he lives on Vatican City grounds.

The Vatican said Francis also invited his household staff 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, struck a modest note as he reflected on 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 had already blown out the candles on his birthday cake, presented to him Saturday by children at the Vatican. But another present awaits him: A delegation from his favorite Argentine soccer team, San Lorenzo, 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, which clinched the Argentine championship Sunday. The delegation flew from Argentina on Monday night on a private plane, to arrive in Rome on Tuesday.