Pope Francis met with U.S. Senator Bernie Sanders in the Vatican on Saturday morning and the two discussed the need for morality in the world economy.

Columbia University Professor Jeffrey Sachs said that the meeting took place in Domus Santa Marta, the pope’s residence, where Sanders had slept Friday night after addressing a Vatican conference on social justice.

Sachs, who has advised the United Nations on climate change, said Sanders thanked the pope for his pronouncements on the need for morality in the global economy and statements in defense of the environment.

"The pope thanked the senator for coming to the meeting and for coming to speak about the moral economy," Sachs said.

The meeting lasted about five minutes, said the economist Jeffrey D. Sachs, an adviser to the Sanders campaign who said he had been present.

The senator’s wife, Jane Sanders, and Msgr. Marcelo Sánchez Sorondo, who organized the conference, were also at the meeting, Mr. Sachs said. Michael Briggs, a spokesman for the Sanders campaign, said no photographs were taken, in accordance with rules at the guesthouse.

“It was a real honor for my wife and I to spend some time with him,” Senator Sanders told The Associated Press on Saturday morning during an interview at a hotel rooftop overlooking St. Peter’s Square. “He is one of the extraordinary figures not only in the world today but in modern world history.”

Pope Francis later confirmed the meeting saying the two men shook hands and that the meeting was not political. “This is called good manners,” the pope said. “If someone thinks that greeting someone means getting involved in politics,” he added, laughing, “I recommend that he find a psychiatrist!”

Even in Rome Sanders encountered enthusiastic supporters. Backers bearing hand-made signs welcomed him as he drove through a gate to enter the Vatican. “Rome is Berning,” one sign said.