Emeritus Pope Benedict XVI has emerged from his self-imposed silence inside the Vatican walls to publish a lengthy letter to one of Italy’s most well-known atheists. In it, he denies having covered up for sexually abusive priests and discusses everything from evolution to the figure of Jesus Christ.

Excerpts of the letter were published Tuesday by La Repubblica, the same newspaper that just two weeks ago published a similar letter from Pope Francis to its own atheist publisher.

The letters indicate that the two men in white — who live across the Vatican gardens from each other — are pursuing an active campaign to engage non-believers. It’s a melding of papacies past and present that has no precedent and signals that the popes — while very different in style, personality and priorities — are of the same mind on many issues and might even be collaborating on them.

Benedict wrote the letter to Piergiorgio Odifreddi, an Italian atheist and mathematician who in 2011 wrote a book “Dear Pope, I’m Writing to You.” The book was Odifreddi’s reaction to Benedict’s classic “Introduction to Christianity,” perhaps his best-known work.

In his book, Odifreddi posed a series of polemical arguments about the Catholic faith, including the church’s sex abuse scandal. The former Cardinal Joseph Ratzinger headed the Vatican office responsible for abuse cases, and was pope when scandal erupted in 2010, with thousands of people coming forward saying they had been molested by priests while the Vatican turned a blind eye.

In his letter, Benedict denies personal responsibility, saying: “I never tried to cover these things up.”

“That the power of evil penetrated so far into the interior world of the faith is a suffering that we must bear, but at the same time we must do everything to prevent it from repeating,” he wrote, according to Repubblica.

While Vatican officials have long insisted that Benedict did more than anyone in the church to confront the problem of abusive clergy, Benedict’s letter marked the first time he himself had publicly denied personal responsibility for the scandal.

Benedict has been seen only a handful of times since his retirement, and only once with Francis at an official Vatican ceremony in July. A prolific writer, he has published nothing since retiring — except for the encyclical “The Light of Faith” which was signed by Francis but was actually written almost entirely by Benedict.

All of which made Repubblica’s publication of his letter all the more remarkable, since it came out of the blue and just two weeks after a letter on almost the exact same subject was penned by Francis on the same pages.

In Benedict’s letter, he takes Odifreddi to task for what he said was the “aggressiveness” of his book, and responds to many of the arguments raised with piqued criticism himself.

“What you say about the figure of Jesus isn’t worthy of your scientific standing,” wrote Benedict, who authored a highly praised, three-volume work on Jesus Christ during his pontificate.

He similarly criticizes Odifreddi’s “religion of mathematics” as “empty” since it doesn’t even consider three fundamental themes for humanity: freedom, love and evil.

On evolution, he wrote: “If you want to substitute God with Nature, the question remains: What does this Nature consist of? Nowhere do you define it and it appears rather like an irrational divinity that doesn’t explain anything.”

Odifreddi, for his part, wrote in an accompanying piece Tuesday that he was stunned to have received the letter, though he said he wrote the book precisely in hopes Benedict might read it.