Two open-air streams trickle west toward the Castle Church in East Germany where Martin Luther nailed his 95 Theses, sparking the Protestant Reformation 500 years ago. (Eliot Stein For The Washington Post)

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.

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