Mayor Michael Nutter and other top Philadelphia officials arrived in Rome Monday to ask Pope Francis to attend a huge Roman Catholic gathering in the city next year.
The delegation, which left Philadelphia International Airport shortly after 6 p.m. Sunday, includes Nutter, Pennsylvania Gov. Tom Corbett and Archbishop Charles Chaput of the Archdiocese of Philadelphia.
They arrived in Rome shortly after after 4 a.m. (EST) Monday and will remain in Italy until Thursday to work with Vatican officials on the eighth World Meeting of Families.
City officials say the September 2015 event could attract more than 1 million people from around the world and be the largest gathering in Philadelphia history.
The Vatican has not confirmed a papal visit to the U.S., but other popes have attended past world family meetings, and family issues are a top priority for Pope Francis.
"I have great confidence that he'll come,'' Chaput said at a news conference where he was joined by the mayor and governor. "We will meet privately with the holy father, and share with him the great excitement and momentum surrounding the meeting in Philadelphia.''
Corbett expects the six-day event to pump $100 million into the local economy.
The World Meeting of Families was last held in Milan in 2012.
Chaput expects a large turnout from South America if Pope Francis -- the former Jorge Mario Bergoglio of Argentina -- attends.
The Philadelphia Archdiocese, with about 1.5 million Catholics, must raise the considerable cost of hosting the event. Chaput said $5 million dollars has been raised so far, but much more is needed. That initially concerned the archbishop, who like many church leaders has faced financial problems that led him to close Catholic schools and parishes.
However, the Vatican had asked the archdiocese to host the event.
"The Vatican doesn't have the means to underwrite the event here, so we'll be raising money,'' Chaput said. "The holy father likes things simple. But any time you have a world leader coming to the city, it's going to take a lot of security and things like that.''
Chaput has put together a roster of influential city business leaders to lead a lay planning committee, including Comcast Chairman Brian Roberts, Aramark Chairman Joseph Neubauer and Daniel J. Hilferty, president of Independence Blue Cross.
The agenda will include keynote speakers and dozens of breakout sessions to help families "grow in grace and holiness,'' Chaput said.
Nutter, who attended a Jesuit prep school, said it would be "an incomparable moment'' for the region to host people from around the world, and perhaps the first Jesuit pope.
NBC10's Jim Rosenfield along with digital managing editor Karen Araiza and photojournalist Jason Ryan arrived in Rome on Saturday. The team is covering the efforts from local leaders to persuade the Pope to come to Philly. Rosenfield report live on NBC10 throughout the week.