As the U.S. Catholic Church continues a three-year "revival" campaign, Bishop Robert Barron is continuing his crusade against "dumbed-down Catholicism" by focusing on the fundamentals of the faith.

The National Eucharistic Revival — launched in 2022 as a grassroots religious movement with support from the U.S. Conference of Catholic Bishops (USCCB) — is described as a campaign to "renew the Church by enkindling a living relationship with the Lord Jesus Christ in the Holy Eucharist" in the face of widespread secularization.

"We [the USCCB] made a decision, I don't know, about four years now to launch this. And it was in response to this Pew Forum study that said 70% of Catholics don't believe in the real presence," Barron told Fox News Digital. "And I'll take a little credit for it. I brought this up in one of our administrative meetings, whatever that was four years ago. And said ‘I think, brothers, we gotta address this problem.'"

US CATHOLIC BISHOPS REAFFIRM ENDING ABORTION AS 'PRE-EMINENT PRIORITY'

Bishop Barron

Bishop Robert Barron of the Diocese of Winona-Rochester, Minnesota, center. (Word on Fire Ministries)

Over the last few decades, orthodox understanding of the Eucharist — the central sacrament of the Catholic faith — has been in precipitous decline.

A Pew Research survey in 2019 found that only one-third of Catholics believed the core doctrine that the Eucharist is the literal body and blood of Jesus.

Other members of the USCCB agreed with Barron's urgency in addressing the issue.

Barron continued, "A number of the committee chairs came to me and said, 'Yeah, we agree with that.' And so we started meeting and came up with the idea of the three-year revival. And then my term ended as chair of evangelization, and I handed the project over to Bishop Drew Cozzens — he's a great guy, bishop of Crookston up here in Minnesota. And he ran with it and, you know, really got this thing off the ground."

VATICAN BLOCKS DOCTRINAL CHANGES ON HOMOSEXUAL RELATIONSHIPS, FEMALE PRIESTS

It is a Holy Communion, studio shot composition.

A priest presents the Eucharist, bread and wine that Catholics believe transforms into the literal flesh and blood of Jesus during the sacrament. (iStock)

Barron, of the Dioceses of Winona-Rochester, 62, is the most widely-followed Catholic cleric on the internet — aside from Pope Francis himself.

The prelate released a book this year, titled "This Is My Body," explaining the theology of the Eucharist as part of the Revival. He says it is aimed at simplicity and orthodox theology, brief by design and inexpensive.

"It's like maybe 100 pages. So it's designed to be, you know, pretty readable," Barron told Fox News Digital. "And we're going through this Eucharistic Revival, right, which is a three-year process. We thought to contribute to it, we'd offer this little book to help individuals and parishes and so on to understand the Eucharist better."

The book has seen sales far exceeding the modest expectations of Barron and his Word on Fire Ministries.

CHRISTIAN LEADERS IN BETHLEHEM DEFEND CANCELING CHRISTMAS CELEBRATIONS TO EMPHASIZE ‘SPIRITUAL MEANING’

Catholics make a procession through Times Square

Over a thousand faithful participate in a Eucharistic Procession through the streets of New York City, following a Mass celebrated by Fr. Mike Schmidt at St. Patrick's Cathedral, sponsored by the Napa Institute. (CNA/Jeffrey Bruno)

Barron said, "I think the first run of the book was 100,000. I remember saying, ‘Oh my gosh, you guys, is that a little too bold to be thinking we could sell 100,000?’ And it turns out we're now at 1.3 million in sales."

The book has been purchased by those seeking Barron's insights as well as in bulk by pastors and bishops interested in freely distributing the slim volume to edify their faith.

"A number of people have purchased individually. I think some parishes and maybe some dioceses, too, for their priests or for their leadership," Barron said.

VATICAN REAFFIRMS 'GRAVE SIN' OF FREEMASONRY, SAYS CATHOLICS CANNOT JOIN THE WORLD'S LARGEST SECRET SOCIETY

Bishop Barron Ordination

Robert Barron prostrates before an altar during his ordination as bishop at the Cathedral of Our Lady of the Angels in Los Angeles. (Brian van der Brug/Los Angeles Times via Getty Images)

Barron sees the book as just one part of his decadeslong campaign against what he believes is the most common cause of Catholic disaffiliation from the faith — poor spiritual instruction from the clerical hierarchy.

"My generation was the first one to get a sort of dumbed-down Catholicism. And we underestimated what people are capable of understanding," Barron told Fox News Digital. "I trace that back to the last 50 or 60 years. And not to blame the [Second Vatican Council], because the Vatican Council called for revival in the Bible and in theology — but in the years after the council, we didn't do catechetics very well, to be honest with you."

He continued, "We simplified and dumbed down the language. And then — when people grew up, and they faced life, and they had a school kid's level of understanding — a lot of them dropped it. And that's one reason for the disaffiliation. […] There was such bad formation intellectually."

Orthodox Eucharist

Eastern Orthodox priests and believers are seen receiving the Eucharist during a service in Zaporizhzhia. (Photo by Andriy Andriyenko/SOPA Images/LightRocket via Getty Images)

CLICK HERE TO GET THE FOX NEWS APP

Belief in the Eucharist is not exclusive to Catholicism — the sacrament is also at the center of historical denominations such as Eastern Orthodoxy, Oriental Orthodoxy and Anglicanism.

The practice can be traced back to the earliest church communities formed in the first and second centuries and is mentioned in the Didache — one of the oldest known treatises on Christian beliefs.

Following the Protestant Reformation in the 16th century, newer Christian denominations began to reexamine belief in the sacrament, with many abandoning the sacrament entirely.