Hill leaders have invited Pope Francis to address a joint session of Congress during his expected visit to the United States next year.

Francis, who on Thursday marked his first anniversary as leader of the world’s 1.2 billion Catholics, is reportedly planning to visit the United States to attend a global conference on families scheduled for late September 2015 in Philadelphia. The trip has not been confirmed, officials with the Vatican and the U.S. Conference of Catholic Bishops said Thursday.

House Speaker John A. Boehner (R-Ohio) issued the invitation as the constitutional officer of Congress, the position that formally invites the president each year to give the State of the Union address. He did so on behalf of House and Senate leaders; minutes after the announcement, House Minority Leader Nancy Pelosi (D-Calif.) said she was pleased to join in making the invitation.

Boehner, however, initiated the idea, aides said.

“This is [Francis’s] one-year anniversary, and John Boehner is Catholic, and so he’s mindful of that,” said Ed Morrissey, a popular conservative commentator and blogger with HotAir.com, and an active Catholic. “But it’s just a measure of how much impact this particular pope is having — everyone wants him there. Who needs it more than Congress, right?”

The Rev. Gerald Fogarty, a historian of Christianity at the University of Virginia who has written on papal visits, said he believed it was the first time a pope has been invited to address Congress. Other popes have visited the White House, including most recently Pope Benedict XVI, who came at the request of President George W. Bush in 2008.

The United States did not have diplomatic relations with the Vatican until 1984. “Our country has a history of anti-Catholicism,” said Sister Mary Ann Walsh, spokeswoman for the bishops’ conference.

Aides to Boehner said he sent the invitation Thursday to officials in Vatican City.

In his formal invitation, Boehner noted that Francis’s ascension to the papacy and his social teachings in the past year “have prompted careful reflection and vigorous dialogue among people of all ideologies and religious views in the United States and throughout a rapidly changing world, particularly among those who champion human dignity, freedom, and social justice.”

Francis’s principles “are among the fundamentals of the American Idea,” Boehner wrote. “And though our nation sometimes fails to live up to these principles, at our best we give them new life as we seek the common good.”

In a separate statement, Pelosi said she has been inspired “by his message of peace, compassion, and brotherhood.”

“Whether inspired by St. Francis of Assisi, who cared for all of God’s creation, or by St. Joseph, protector of the church, Pope Francis has lived his values and upheld his promise to be a moral force, to protect the poor and the needy, to serve as a champion of the less fortunate, and to promote love and understanding among faiths and nations,” Pelosi said.

Many politicians have claimed to be in policy alliance with the pope, and on Thursday some pope-watchers were already challenging the alliance between the capitalism-skeptical pope and the leading Republican.

“Does Boehner realize Pope Francis is to the left of [President] Obama on many issues? Then again 2015 not an elex year,” tweeted David Gibson, a papal biographer who covers the church. “John Boehner invites Latino who speaks no English to address Congress in support of immigrants. Sure, it’s Pope Francis. But still.”