Speaker of the House John Boehner has extended an open invitation to Pope Francis to address a joint meeting of Congress, praising the Pope's advocacy for the vulnerable.

"Pope Francis has inspired millions of Americans with his pastoral manner and servant leadership, challenging all people to lead lives of mercy, forgiveness, solidarity, and humble service," Speaker Boehner said March 13.

"His tireless call for the protection of the most vulnerable among us-the ailing, the disadvantaged, the unemployed, the impoverished, the unborn-has awakened hearts on every continent."

Speaker Boehner said such an address from the Pope would "honor our nation in keeping with the best traditions of our democratic institutions" and would be an opportunity for the American people and the world to "hear his message in full."

Boehner, an Ohio Republican who is Catholic, said the Pope's pastoral message "challenges people of all faiths and political parties."

House Minority Leader Nancy Pelosi, a California Democrat who is Catholic, joined the invitation.

"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," she said in a separate statement.

The invitation came on the first anniversary of Pope Francis' election to the papacy.

No Pope has ever addressed Congress, the U.S. House Historian's office told USA Today.

Speaker Boehner said Pope Francis' social teachings are rooted in "the joy of the gospel" and have prompted "careful reflection and vigorous dialogue" among people of all political and religious views, "particularly among those who champion human dignity, freedom and social justice."

He said the Pope's principles are "among the fundamentals of the American Idea."

"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," he said.