NEW YORK — A year from this month will mark five centuries since a Catholic monk in a backwater German town denounced church abuses by nailing a list of propositions to the door of the local cathedral — an act of defiance that turned out to be one of the most fateful moments in world history.

Martin Luther went on to become synonymous with the concept of speaking truth to power, and the date of his provocation, Oct. 31, 1517, has long been viewed as the official starting point for the Protestant Reformation that would sunder Christendom and trigger a series of vicious conflicts and political realignments that reshaped Europe.

Yet even as Christian leaders and scholars of religion use this anniversary to gauge why the Reformation happened, and how to mark and heal the rift, a landmark exhibit that opened Friday at the Morgan Library shows how Luther’s legacy is also as relevant and immediate as a Facebook feed.

The New York exhibition, “Word and Image: Martin Luther’s Reformation,” is in fact one of three interconnected U.S. shows that, taken together, represent the most extensive display of Luther-related materials ever collected outside of Germany.

The others are an exhibition at the Minneapolis Institute of Art that opens Oct. 30 and focuses on the cultural and historical context of the Reformation; and an exhibit opening Oct. 11 at Emory University in Atlanta that examines the debates over the law, grace and salvation that animated Luther and his followers.

The Morgan Library exhibit features a range of remarkable pieces, including an iconic portrait of Luther by his friend and neighbor in Wittenberg, the artist Lucas Cranach.

There’s also a wooden money chest used by Johann Tetzel, a Dominican friar who gained infamy — and spurred Luther’s anger — for taking payments in exchange for granting indulgences, which are remissions of punishment for sin.

But the centerpiece of the New York exhibit, as befits the library’s focus, is a set of documents associated with Luther and his remarkable ability to communicate with the wider populace. There are his translations of the Bible from Latin into the German of the day, as well as Lutheran hymnals and Luther’s 1521 letter to the Holy Roman Emperor, Charles V, in which Luther stood by the theological views that were earning him both renown and powerful enemies.

The real jewel, however, the item that delivers a frisson of physical connection to a distant past, is a single page print of the famous 95 Theses that Luther nailed to the door of the Wittenberg cathedral, one of just six contemporaneous copies in existence.

Martin Luther, The Ninety-Five Theses, broadside. (Photo courtesy of the Morgan Library & Museum.)
Martin Luther, The Ninety-Five Theses, broadside. (Photo courtesy of the Morgan Library & Museum.)

That even these few copies survive is a small miracle, said John McQuillen, who curated the exhibition. Wittenberg was a university town, and the cathedral doors “were the bulletin board of the university,” he said, where it was standard practice to post a notice of a debate and the points that you wanted to argue.

That’s all Luther was really doing.

“I don’t think it was this dramatic moment of the sound of the hammer ringing across Germany,” McQuillen said. “It was another day at the university, and another lecture to be held.”

No one knows if Luther actually posted a printed copy like the one on display here, or if it was handwritten. If it had been a written version it would not have been considered worth saving, nor would it have survived — handwritten copies were cast aside as a matter of course once a printed version was available; a written original was considered of no value until modern times, and no one then realized the impact that these 95 Theses would have.

Even these famed theses may not have been as important as the world has come to believe.

They were, after all, written in Latin and intended for a university audience of theologians. What really had an impact was a sermon on many of these same topics — indulgences and grace and corruption in the church – that Luther delivered a short time later and had printed up and distributed.

That sermon arguably had a much greater effect on the wider public and marked the start of Luther’s career as an astonishingly proficient writer, publishing a sermon or pamphlet or book on an average of every three weeks up until his death in 1546.

Movable type printing — invented in Europe six decades earlier by Luther’s fellow German, Johannes Gutenberg — was gaining steam as an industry, and Luther and the popularity of his ideas gave printers an enormous boost.

McQuillen stressed that the success of the Reformation was really the result of a kind of “perfect storm” of conditions as much as Luther’s theological concepts: Sentiment in Germany was already growing against the church’s corrupt practices, as was resentment that so much money was going to Rome instead of staying closer to home.

In addition, local princes were looking for more autonomy and were willing to protect Luther when the forces of church and empire were out for his head — a campaign that also brought Luther fame, and more grass-roots support.

But it was the combination of a new technology and a new theology — and, as McQuillen said, “someone who knew that message had to get out with little short texts that were very understandable to the average reader” — that made the difference.

Luther, working with Cranach and his shop of painters and engravers, was also able to distribute mass-produced woodcut images that mocked the pope or showed charity workers in a positive light.

“He took the message to the people. It is like 16th-century tweeting – throwing out these little pamphlets, these little single-page tracts, and almost poster prints of eye-catching woodcut illustrations,” McQuillen said.

It was as big a shift as the transition 1,500 years before Luther from scrolls to the bound codex, and it changed the Western world, religiously, politically and culturally.

“We are on a continuum of media. This is not something that was just invented with Facebook and Twitter,” McQuillen said. “We perpetually revisit the way that information gets out, how and what it is. And the fact that we are still dealing with the same problems and issues that they were dealing with 500 years ago is very telling to how important this subject matter is.”

From Martin Luther to Bernie Sanders to, yes, perhaps, Donald Trump – the medium is the message, once again.

Luther’s life “is almost ridiculously relevant today as to how a grass-roots movement gets going and actually can change something,” McQuillen said.

(“Word and Image: Martin Luther’s Reformation” runs through Jan. 22, 2017, at the Morgan Library & Museum in New York)