U.S. Ambassador Kenneth Hackett greets Archbishop Chaput in Rome Monday night, March 24, prior to the meetings with Vatican planners for the 2015 World Meeting of Families in Philadelphia. Philadelphia Mayor Michael Nutter, left, and Pennsylvania Gov. Tom Corbett look on.

Ambassador Hackett greets Archbishop Chaput.

Gov. Tom Corbett meets Ambassador Kenneth Hackett, with his wife Joan.

Philadelphia Mayor Michael Nutter (right) meets Kenneth Hackett, U.S. ambassador to the Holy See.

Archbishop Chaput celebrates Mass along with Bishop John McIntyre (right) and Father William Donovan, a priest of the Philadelphia Archdiocese. (Chris Warde-Jones)

Archbishop Charles Chaput preaches the homily during Mass March 25 in a chapel of St. Peter’s Basilica for the Pennsylvania delegation in Rome to plan for the 2015 World Meeting of Families in Philadelphia. (Chris Warde-Jones)

Donna Farrell, executive director of the 2015 World Meeting of Families, reads the first reading during Mass in a chapel of St. Peter’s Basilica March 25. (Chris Warde-Jones)

Gov. Tom Corbett and and his wife Susan (center) meet with Joan Hackett, wife of U.S. Ambassador to the Vatican Ken Hackett.

Main Line businessman Eustace Mita (left) and his wife Susanne share the dais with Archbishop Chaput during the press conference on the 2015 World Meeting of Families March 25 in Rome. (Chris Warde-Jones)

Philadelphia Auxiliary Bishop John J. McIntyre, Philadelphia Mayor Michael Nutter, Archbishop Vincenzo Paglia, president of the Pontifical Council for the Family, Pennsylvania Gov. Tom Corbett , Philadelphia Archbishop Charles J. Chaput, Bishop Jean Laffitte, secretary of the Pontifical Council for the Family, and Everett A. Gillison, chief of staff for Mayor Nutter, pose for a photo after a press conference March 25 to discuss the September 2015 World Meeting of Families in Philadelphia. (CNS photo/Paul Haring)

Eustace and Susanne Mita, Archbishop Charles J. Chaput of Philadelphia, Archbishop Vincenzo Paglia, president of the Pontifical Council for the Family, and Jesuit Father Federico Lombardi, the Vatican spokesman, participate in a press conference with a delegation from Pennsylvania at the Vatican March 25 to discuss the September 2015 World Meeting of Families in Philadelphia. (CNS photo/Paul Haring)

Archbishop Charles J. Chaput of Philadelphia, center, looks on as Archbishop Vincenzo Paglia, president of the Pontifical Council for the Family, right, speaks during a press conference with a delegation from Pennsylvania at the Vatican March 25 to discuss the September 2015 World Meeting of Families in Philadelphia. (CNS photo/Paul Haring)

Archbishop Charles J. Chaput of Philadelphia speaks during a press conference with a delegation from Pennsylvania at the Vatican March 25. (CNS photo/Paul Haring)

Archbishop Charles J. Chaput signs a ceremonial contract assigning the World Meeting of Families to the city of Philadelphia in 2015 while leaders of the Pontifical Council for the Family Archbishop Vincenzo Paglia (left) and Bishop Jean Laffitte look on with Auxiliary Bishop John J. McIntyre (far right). (Chris Warde-Jones)

Pennsylvania Gov. Tom Corbett and his wife Susan receive a gift from Archbishop Vincenzo Paglia March 25 during a press conference at the Holy See Press Office in Rome. (Chris Warde-Jones)

Pope Francis gets his first look at the Liberty Bell. Learn how you can help build the buzz to invite the pope to Philadelphia for the World Meeting of Families — where he can see the real Liberty Bell.

Mayor Nutter chats with Pope Francis at the Vatican March 25.

Mayor Nutter gets a grateful response from Pope Francis of the gift of his personalized jersey.

Mayor Nutter holds the jersey that he intended to give Pope Francis as a personal gift when they met later in the day on March 25 after the pope’s general audience.

Pope Francis accepts the gift of a replica of the Liberty Bell from Philadelphia Mayor Michael Nutter, as Archbishop Charles Chaput looks on.

Members of the Pennsylvania delegation meet Pope Francis during his weekly general audience at the Vatican.

Pope Francis greets Archbishop Charles J. Chaput of Philadelphia during his general audience in St. Peter’s Square at the Vatican March 26. (CNS photo/Paul Haring)

Philadelphia Mayor Michael Nutter holds up a replica of the Liberty Bell as he waits to greet Pope Francis during the pontiff’s general audience in St. Peter’s Square at the Vatican March 26. (CNS photo/Paul Haring)