Boehner told the assembled reporters he had planned to leave Congress at the end of 2014, but his plans changed after his chief deputy and likely successor, Majority Leader Eric Cantor, lost in one of the biggest electoral upsets in U.S. history. Boehner’s decision comes just a day after what was arguably his most memorable moment as speaker: The Irish Catholic son of a barkeep hosted Pope Francis in the first-ever address by a pontiff to Congress. And it seemed the pope’s message had at least some impact on the timing of the speaker’s decision.

Boehner said he had originally wanted to announce on November 17—his 66th birthday—that he would step down at the end of the year. But the conservative threat to depose him moved up the timetable, and when he woke up Friday on the morning after meeting the pope, he said to himself, “Today is the day I’m going to do this.”

He resisted, however, the notion that conservatives had forced his hand.

“I can tell you, if I wasn’t planning on leaving here soon, I would not have done this,” Boehner said. The famously-emotional speaker broke down several times during his 15-minute news conference, most notably when he recounted a private moment he shared with Pope Francis. As they were leaving the Capitol on Thursday, the pontiff took the speaker aside and asked him to pray for him. “Who am I to pray for the pope,” a deeply-humbled Boehner told reporters. “But I did.”

By ballot or by pressure, conservatives have now succeeded in toppling the top two Republican leaders of the House within a span of 15 months. Boehner’s announcement sets off a race to succeed him, with Majority Leader Kevin McCarthy of California, the second-ranking Republican in the House, the early favorite to take his post. Another popular House Republican, Representative Paul Ryan, immediately took himself out of the running, according to the Washington Post’s Paul Kane. “It’s McCarthy,” the 2012 GOP vice presidential nominee said Friday. Ryan later put out a statement in which he called Boehner’s decision to resign “an act of pure selflessness.”

Boehner, 65, was first elected to the House in 1990 and, as he frequently reminds reporters, was himself part of a group of conservative rabble-rousers during his first decade in Congress. He rose to a position in the leadership before being ousted in 1998. He returned to committee work, playing a key role in the passage of the No Child Left Behind Act under President George W. Bush. Boehner then worked his way back up the leadership ladder, first becoming minority leader and then speaker after Republicans reclaimed the House majority in the 2010 election.

While it was well-known that Boehner’s job was in jeopardy, his announcement Friday morning came as a shock. He has insisted in recent weeks that he was unconcerned about the potential conservative mutiny, with his spokesmen saying he wasn’t “going anywhere.” But the end came rapidly, less than 24 hours after Boehner stood weeping next to the pontiff on a Capitol balcony, overlooking throngs of people gathered to see Pope Francis.