The former pope Benedict XVI has requested the removal of his name as the co-author of a controversial new book in which he spoke out against allowing married men to become priests as a dispute over its publication gripped the Vatican for a third day.

“I can confirm that this morning I acted on instructions from the emeritus pope and I asked Cardinal Robert Sarah to contact the book’s publishers and request them to remove Benedict XVI’s name as co-author of the book and remove his signature from the introduction and the conclusions too,” the retired pontiff’s personal secretary, Georg Gänswein, told the Italian news agency Ansa on Tuesday.

Benedict’s intervention in the book From the Depths of Our Hearts has come weeks before his reform-minded successor Francis is expected to publish a document on whether married men may be ordained in the Amazon as a solution to a priest shortage there.

The controversy over the book underscores the conservative-progressive battle lines that have exploded in the Catholic church following Benedict’s decision in 2013 to become the first pope in 600 years to retire.

Extracts of the book published by France’s Le Figaro newspaper on Sunday ignited a fresh round of briefings from backers of the current pope and traditionalists nostalgic for Benedict’s orthodoxy. The book is published in France on Wednesday.

Francis’s supporters claimed the increasingly frail Benedict, 92, had been manipulated by members of his rightwing entourage into writing something that amounted to a frontal attack on Francis.

Sarah, who heads the Vatican’s liturgy office and co-authored the book with Benedict, posted to Twitter a series of letters from the former pope late on Monday making clear he had written the text and approved its publication after news reports quoting “sources close to Benedict” claimed he never saw or approved the finished product.

“I solemnly affirm that Benedict XVI knew that our project would take the form of a book. I can say that we exchanged many drafts to make corrections,” he said.

Des attaques semblent insinuer un mensonge de ma part. Ces diffamations sont d’une gravité exceptionnelle. Je donne dès ce soir les premières preuves de ma proche collaboration avec Benoît XVI pour écrire ce texte en faveur du célibat. Je m’exprimerai demain si nécessaire. +RS pic.twitter.com/L8Q6NmkXKE — Cardinal R. Sarah (@Card_R_Sarah) January 13, 2020

Gänswein, however, told Ansa that “Benedict did not approve a project for a co-authored book and he had not seen or authorised the cover” and therefore asked the publishers to remove Benedict’s name from the cover, the introduction and the conclusion.

“The pope emeritus knew that the cardinal was preparing a book and he sent him a text on the priesthood authorising him to use it as he wanted. But he did not approve a project for a co-authored book, and he had not seen or authorised the cover.”

Gänswein said it was “a misunderstanding that does not raise questions about Cardinal Sarah’s good faith”.

Sarah tweeted minutes later that future publications of the book would name him as the sole author “with the contribution of Benedict XVI”.

“Considering the controversies that provoked the publication of the book From the Depths of Our Hearts, it is decided that the author of the book will be for the further publications: Cardinal Sarah, with the contribution of Benedict XVI,” he said. “However, the full text remains absolutely unchanged.”

Benedict’s intervention had been seen as surprising since he had vowed to live “hidden from the world” when he retired in 2013, specifically to avoid any suggestion that he still wielded papal authority. He has come forward on various issues over the past seven years, but this is the first time he has intervened on a matter that the more liberal Pope Francis is actively considering.

The Vatican insisted the book was a mere “contribution” to the discussion about priestly celibacy written by two bishops in “filial obedience” to Francis.