Five hundred years after Martin Luther ignited the Protestant Reformation, dividing Christianity, only about half of American Protestants embrace some of his core beliefs. Many don't even know what the Reformation is.

In fact, most American Protestants now believe that Catholics — enemies for centuries in bloody religious wars across Europe — are more like them than different, according to a survey released this week by the Washington, D.C.-based Pew Research Center.

The survey comes as Protestants worldwide gear up for the October commemoration of the day Luther nailed 95 theses — criticisms of the Catholic Church — to a church door in Germany. More than half of Minnesotans are Protestant, including a million Lutherans — the largest number in the nation.

While the majority of older Protestants are aware of their history, the 16th-century reformer is hardly a superstar among 21st-century young adults. The survey showed that 1 of 3 Americans ages 18 to 29 didn't know that Luther inspired the Reformation.

And just over half of the young adults were able to identify "The Reformation" as the period in which Protestants broke from the Catholic Church. Nearly 1 in 4 said it was "The Great Crusade."

The findings didn't surprise Hans Wiersma, a religion professor at Augsburg College in Minneapolis. Students increasingly are showing up for religion class with scarce knowledge of Christian history and tenets.

"Even if they were paying attention during Confirmation [classes], they've already forgotten it," Wiersma said.

The survey by Pew, one of the nation's top religion research groups, offered a glimpse into Luther's legacy today.

It was designed to test a couple of questions, said Greg Smith, associate research director. What do people know about the Reformation? How do Catholics and Protestants view each other today? What do people today think of the key controversies of the era?

While Catholics and Protestants today often are divided by issues such as abortion and sexuality, two burning issues 500 years ago were: How do you get to heaven? And what's the source of God's message on Earth?

Survey-takers were asked about both.

Luther had argued that "faith alone" was the key to salvation, in contrast to the Catholic belief that faith and good deeds were required. Only 46 percent of Protestants today agreed with Luther.

That number, however, varied widely among Protestants. White evangelicals overwhelmingly agreed with Luther, with 67 percent saying faith alone was the ticket. That compared with 37 percent of white mainline Protestants and 29 percent of black Protestants.

White evangelicals, it turned out, could be Luther's kindred spirits today.

"White evangelical Protestants are more likely than others to espouse beliefs in line with the beliefs espoused by Protestant reformers 500 years ago," Smith said.

The Bible as God's sole source of authority was the second Luther tenet asked about in the survey. More than 50 percent of Protestants agreed with the Catholic position on the issue, which is that the faithful need both the Bible and "guidance from church teaching, traditions."

The survey reflects a gradual erosion of theological differences held by folks in the pews.

Likewise, historic animosity between Catholics and Protestants has eroded, the survey showed. Fifty-seven percent of Protestants surveyed said they believed Catholics were more similar than different, as did 65 percent of Catholics surveyed.

The Rev. Ben Cieslik, of Bethlehem Lutheran Church in Minneapolis, said the findings may reveal less about Protestants shifting their religious beliefs than it does about Protestants being unfamiliar with formal doctrine. He acknowledges that educating the faithful about a religion's core religious positions is not easy.

"I can't go up to the pulpit and say, 'You have to believe in faith alone, or in the Bible alone,' " Cieslik said. "You have to help people understand how it's true for their lives today."

The survey is the first focusing on Reformation history by Pew Research, which has tracked religious trends for more than a decade. It was based on a survey of more than 2,500 respondents, with an overall margin of error of 2.9 percentage points.

Pew's Smith said he hopes to continue research on Luther's legacy.

"I'd love to have asked about other issues at play during the Reformation, about indulgences, the role of the priesthood, about transubstantiation," he said, referring to the doctrine behind the Catholic sacrament in which bread and wine are converted into Jesus' body and blood.

Jean Hopfensperger • 612-673-4511