Pope Emeritus Benedict XVI's longtime aide is pushing to have the retired pontiff removed as co-author of a controversial book on priestly celibacy.

Benedict’s aide, Archbishop Georg Gänswein, alleged that the retired pope never intended to have his name on the book — there had been a “misunderstanding” with the other co-author, Cardinal Robert Sarah.

But in tweets and statements Tuesday, Sarah defended himself, saying that Benedict, 92, had been fully informed and signed off on the plans.

Given the dispute, Sarah wrote, Benedict would be removed as co-author and instead listed as a contributor.

“However,” Sarah said, “the complete text remains absolutely unchanged.”

The book’s English-language publisher said it still considered Benedict a co-author.

The back-and-forth between Benedict’s main lieutenant and a conservative cardinal mirrored a larger debate inside the Catholic Church over what kind of role the retired pope should have — and whether he risks being manipulated as he grows more frail.

Benedict vowed after abdicating that he would remain silent on major church affairs. But in two high-profile cases in the past year, on the topics of sexual abuse and celibacy, he has shared opinions that either contradict Francis or put pressure on him.

“The one good thing from this whole cheap operetta is that it’s now clearly demonstrated to show that the whole [pope] emeritus thing doesn’t work,” said Ulrich Lehner, a theology professor at the University of Notre Dame.

The new book amounts to an ardent defense of clerical celibacy at a time when Francis is considering allowing married deacons to become priests in the Amazon region, to address priest shortages. According to excerpts published Sunday by France’s Le Figaro newspaper, Benedict wrote that celibacy was a sometimes painful but necessary “criterion” for ministry.

The question of Benedict’s role in the book has consumed a slice of American Catholicism, with social media posts flying about who was probably telling the truth. Conservatives have been angered by the suggestion that Sarah — a traditionalist stalwart — had duped Benedict or that Benedict wasn’t challenging Francis, while more-liberal Catholics accused the emeritus pope of trying to undermine Francis.

John L. Allen Jr., editor of the Catholic news site Crux and a biographer of Benedict, said Tuesday that despite the fracas, Benedict and Francis were on the same side of the celibacy debate.

“They are both willing to entertain limited exceptions,” said Allen, noting that Benedict allowed married Anglican converts to become Catholic priests.

“I think this is less about pope versus pope than about rival camps in the church seeking to exploit both popes,” Allen said.

In a statement to Italy’s ANSA news service, Gänswein, Benedict’s personal secretary, said the retired pope had never approved the project as co-author and had not “seen or authorized the cover,” which included his photo. Gänswein called it “a misunderstanding that does not raise questions about Cardinal Sarah’s good faith.” Gänswein also asked that Benedict’s name be removed from introductory and concluding sections.

Sarah, the head of the Vatican’s liturgical office, provided a different — though not entirely contradictory — narrative, sharing several letters written to him by Benedict in late 2019. Sarah said he asked the pope emeritus in September if he might be willing to share reflections on the priesthood, paying particular attention to the topic of celibacy.

Sarah said he cautioned Benedict that the subject might raise “debate” in newspapers.

“But I am convinced that the whole church needs such a gift,” Sarah said he told Benedict.

Benedict replied that he had already started writing along those lines but hadn’t felt good about the work he was producing.

“Then came your letter, with the unexpected request of a text directly on priesthood with particular attention to celibacy,” Benedict wrote. “So I reprised my work and will forward to you the text.”

He sent that text in October, according to Sarah, and offered a final thank you in November.

“As for me, the text can be published in the way you planned,” Benedict wrote.

Stefano Pitrelli in Rome contributed to this report.