Catholics and Muslims have come a long way since the Crusades, but during the tenure of Pope Benedict XVI, relations between the world’s two largest religions hit the skids.
So it was with relief and renewed optimism that prominent Muslims and interfaith advocates cheered the newly anointed Pope Francis.
"We are hoping for better relations with the Vatican after the election of the new pope," Mahmud Azab, adviser for inter-faith affairs at Al-Azhar, Sunni Islam's highest seat of learning in Cairo, told AFP. "We congratulate the Church of St. Peter and all Catholics around the world."
From the start, Benedict put less energy in reaching out to other religions than his predecessor, Pope John Paul II, who blazed the trail for Catholic relations with Muslims and other religions through his tireless travels and scores of meetings and prayer with imams around the world.
Under John Paul, the Vatican launched the World Day of Prayer for Peace in 1986, which was at first a hard sell for prominent Muslims, said Father Thomas Michel, who has a PhD in Islamic studies and headed John Paul’s office for Islam for 13 years.
"By the second one [World Day of Prayer for Peace in 1993] Muslims could see he didn’t have any other agenda — that he wasn’t going to get them all together and convince them to become Christians," said Michel, now a professor of Christian-Muslim relations at Georgetown University.
"By the time of the third, in 2002, there were so many leaders of Muslims organizations there wasn’t room for them on the podium… I don’t think Muslims changed so much, but what changed was the level of trust."
Mohammed brought 'evil and inhuman'
But when Benedict gave a controversial speech at the University of Regensburg in Germany in 2006 — a little more than a year after his installation as pope — he sparked fury across the Muslim world by quoting a Byzantine Emperor as saying, "show me just what Mohammed brought that was new and there you will find things only evil and inhuman."
In response to the pope's comments — though some argued they had been misunderstood — 138 leading Muslim scholars from around the world signed an open letter of protest to Benedict. In some countries there were protests and attacks on churches.
"It was a very strained period of the relationship," said John Esposito, professor of International Affairs and Islamic Studies at Georgetown University.
The Vatican took measures to patch up the fallout from Regensburg speech — which Vatican officials reportedly called "the accident."
They held formal meetings with the Muslim leaders who had launched a "common word" initiative emphasizing the shared principles at the core of Christian and Islamic scriptures.
In October 2006, Benedict traveled to Turkey, making a symbolic visit to the ornate Blue Mosque in Instanbul where he emphasized his desire for reconciliation between Muslims and Christians.
And in 2009, Benedict traveled to Jordan and visited the site where Jesus was baptized, emphasizing the "common history" of Christianity and Islam. Even so, he stopped short of praying with his Muslim hosts in a mosque, or taking his shoes off to enter the prayer hall.
Dialogue resumed, but the relationship remained cool.
There are some early signs that Pope Francis could pick up where Pope John Paul II left off.
Reports from Argentina citing local Muslim leaders suggest that Francis — formerly Cardinal Jorge Bergoglio, the Archbishop of Buenos Aires — was a friend to the Muslim community.
One report out of the country said that in 2006 Bergoglio spoke out against the Regensburg speech, according to the Daily Telegraph of London.
Quick response to Francis
"Pope Benedict's statements don't reflect my own opinions," he said in a local press interview, according to the report. "These statements will serve to destroy in 20 seconds the careful construction of a relationship with Islam that Pope John Paul II built over the last twenty years."
That report has not been confirmed by NBC News.
But a lot of Muslim optimism about Francis is based simply on hunches about his character.
The initial impression of the pope — as a man who values simplicity, openness, and the ability to connect with all people — is appealing to Muslims, said Esposito.
For the new pope’s installation ceremony, he noted: "They went out of their way to talk about how people of all major faiths are invited. From the other side, it’s interesting to see how quick Muslims were… to say how they look forward to working with him."
He referred to public statements issued by prominent imams as well as larger Muslim civil rights groups including the Council on American Islamic Relations and the Muslim Public Affairs Council.
Michel saw the same optimism about Pope Francis in a flood of email from Muslims.
"They are so happy and looking forward to working with him," he said. "He’s coming in as every pope does with a real fund of good will and they are really hoping that he will be someone he can work with."
Building trust and influence
If Francis establishes a relationship of trust with Muslims, it could have impact beyond just warm and fuzzy feelings, some observers believe.
A pope with a new approach could be important in a Muslim-majority country like Pakistan, where minority Christians -- most of them Catholics -- suffer persecution, says Jeff Siddique, a Muslim-American in Seattle who was born in Pakistan.
"If (Pope Francis) can build a relationship with the leadership in Pakistan, he may be able to convince them that protecting the Christians in Pakistan is a good thing to do," he said.
Likewise, he may be able to restart discussions with Al-Azhar University in Egypt, which cut off dialogue with the Vatican in 2011 after Benedict called for greater protections for non-Muslims after a suicide bomber attacked a church in Egypt, killing 23 people. Al-Azhar cut ties over what it said was Benedict’s "repeated treatment of Islam in a negative way."
To have an influence across religions requires a foundation of trust, said Michel.
"When they trust each other they can speak freely," he said. "If people come on as scolds or know-it-alls, they get their backs up and won’t accept it."
For some seeking clues about the pontiff’s position on Christian-Muslim relations, his choice of Francis — after Francis of Assisi — has significance beyond his emphasis on simplicity and concern for the poor and downtrodden.
A 13th century story describes how St. Francis left the camp of the crusaders who were attacking the walled Egyptian city of Damietta, and dared to cross enemy lines to meet with Malik al-Kamil, the sultan of Egypt. He risked being killed, but instead, he had a fruitful conversation with the Muslim leader and left unharmed.
The encounter is played up in newer biographies as a pivotal moment of engagement between the two religions.
"We’re seeing the church interpret Francis in modern times as a bridge," said Paul Moses, author of "The Saint and the Sultan," a 2009 book which explores the encounter. "To Muslims ears, the choice of Francis for a name should sound good," he told Religion News Service.
Did Francis choose this name as an overture to Muslims?
"I’d say that it’s pushing it to say this was a factor," said Michel. Nonetheless, he said other signs favor improving ties — from both sides of the divide.
"I get the feeling of 'let's start over, let's start a new chapter. The last one was bumpy'."