This year marks the 500th anniversary of the Protestant Reformation, the breaking point that cleaved Western Christianity in two. Half a millennium later, the bloody wars between Protestants and the Catholic societies they broke away from have long ceased, but the churches remain divided.

What beliefs really separate the Protestant and Catholic adherents of today, though? The Pew Research Center created a survey that found some surprising results.

We’ve distilled the results into a three-question quiz. See what you know, then find out what modern-day Christians believe. (If the quiz isn’t displaying in your browser, try clicking here.)

Kathleen Crowther, a historian who specializes in the Protestant Reformation, said during a panel discussing the results at the Religion News Association meeting in Nashville last week that she wasn’t surprised to hear that Protestants today don’t fully embrace Luther’s teachings, especially sola fide. Luther was reacting to corrupt practices of the church in 1517, like charging money to guarantee a loved one’s passage out of purgatory, when he said that good works won’t gain someone passage to heaven. “It’s one thing to say that buying and selling indulgences is crass and wrong,” Crowther said. “It’s another to say that giving charity to your neighbor is on a plane with buying indulgences. This is one thing they really struggled with, and I think Protestants do today.”

Another historian who has written extensively about the Reformation, Thomas Albert Howard, responded to the survey by noting that the blurring of these theological differences helps keep the peace between Catholics and Protestants, who fought one another on battlefields across Europe for years. “Sometimes just forgetting things, forgetting the difficult things in the past, is one way for human solidarity,” he said.

But the differences aren’t all so erasable. Howard theorized that if Pew had asked Protestants more questions about the role of the Virgin Mary in their worship or about their attitudes toward the papacy, the survey would have found that Protestants still sharply diverge from Catholics on those points.

Click here to read the complete Pew study.

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