A senior Vatican official told Bloomberg that Sanders showed “monumental discourtesy” in reaching out for an invitation to next week’s conference hosted by the Pontifical Academy of Social Sciences. Sanders said on MSNBC Friday morning that he was “grateful” to be invited to speak at the conference about climate change and creating a “moral economy that works for all of the people.”

But Margaret Archer, the president of the Pontifical Academy of Social Sciences, told Bloomberg that Sanders committed a faux pas by reaching out for an invitation. “Sanders made the first move, for the obvious reasons,” Archer said. “I think in a sense he may be going for the Catholic vote but this is not the Catholic vote and he should remember that and act accordingly—not that he will.”

However, Reuters reported that Sanders was, in fact, invited by an aid who works closely with the Pope, Monsignor Marcelo Sanchez Sorondo. He is chancellor of the Pontifical Academy of Social Sciences, a position above the president of the organization, and according to Reuters said of Archer’s comments, “I deny that. It was not that way. This is not true and she knows it. I invited him with her consensus.”

Reuters also received an email containing a March 30th invitation to Sanders signed by Sorondo.

Sanders has repeatedly expressed admiration for Pope Francis on the campaign trail. “I am delighted to have been invited by the Vatican to a meeting on restoring social justice and environmental sustainability to the world economy,” Sanders said in a statement to The New York Times. “Pope Francis has made clear that we must overcome ‘the globalization of indifference’ in order to reduce economic inequalities, stop financial corruption and protect the natural environment. That is our challenge in the United States and in the world.”

He will head to the Vatican immediately after debating Hillary Clinton in Brooklyn on April 14, according to The Washington Post.