Correction: An earlier version of this story incorrectly said that John R. Sellers is in charge of Civil War papers at the Library of Congress. Sellers has retired. This story has been updated to reflect the correct information.

A 1905 artist's rendering of what it may have looked like when President Abraham Lincoln delivered his famous Gettysburg Address at the dedication of the Gettysburg National Cemetery. (Library of Congress/Associated Press)

It was the biggest assignment of Joseph Ignatius Gilbert’s journalistic career — and he was in serious danger of blowing it.

On November 19, 1863, the 21-year-old Associated Press (AP) freelancer was overlooking the battlefield at Gettysburg, Pennsylvania. Towering above him was Abraham Lincoln.

Lincoln had come to dedicate a portion of the battlefield as a national cemetery. Gilbert, who had been covering Lincoln for 21 / 2 years, was taking down the president’s words when something odd happened.

He became star-struck.

“Fascinated by Lincoln’s intense earnestness and depth of feeling, I unconsciously stopped taking notes,” he would recall decades later, “and looked up at him just as he glanced from his manuscript with a faraway look in his eyes as if appealing from the few thousands before him to the invisible audience of countless millions whom his words were to reach.”

Luckily for Gilbert, Lincoln allowed his text to be copied while the ceremonies ended. And “the press report was made from the copy,” the reporter noted.

Brief as Lincoln’s speech was, many newspaper reports didn’t use his exact words. One hundred fifty years later, the debate continues over exactly what Lincoln said that day.

The speech contains about 270 words. Today, a listener with a smartphone could repeat it in 10 tweets. But back then, the news medium was a reporter taking notes with a pencil.

Once finished, he would race to a telegraph office and hand over his dispatch to an operator, who would tap it out in Morse code (a series of long and short sounds). The story would travel to a newspaper office, where the code was turned back into words, then the story was laid out for printing.

For a great many papers, the source of Lincoln’s speech was the AP. But were those the words Lincoln spoke?

There are five known drafts of the speech in Lincoln’s handwriting, each different from the other in some small or not-so-small way. The last, written in March 1864, is the version on the Lincoln Memorial.

In 1894, Lincoln’s personal secretary, John Nicolay, published what he called “the autograph manuscript” of the Gettysburg Address.

Martin P. Johnson, an assistant history professor at Miami University in Ohio, believes that this is the draft Lincoln pulled from his coat that day. John R. Sellers, retired curator of Civil War papers at the Library of Congress, agrees. (See the copy here:

But historian Gabor Boritt argues that a version discovered in 1908 among the papers of John M. Hay, Lincoln’s assistant secretary, is the one from which the president read.

(Perhaps the most important difference among the versions is the presence or absence of the phrase “under God.”)

But why does it matter which copy is the one Lincoln read that day?

“The exact words are important because they clearly reveal Lincoln’s thinking about the importance of the Civil War and the world historical importance of the struggle that he was engaged in,” Johnson said.

Associated Press