GETTYSBURG, Pa. — On the Civil War battlefield where President Abraham Lincoln gave a speech that symbolized his presidency and the sacrifices made by Union and Confederate forces, historians and everyday Americans gathered Tuesday to ponder what the Gettysburg Address has meant to the nation.

Civil War historian James McPherson and U.S. Interior Secretary Sally Jewell were scheduled to speak to mark the 150th anniversary of speech. Pennsylvania Gov. Tom Corbett also will deliver remarks.

It comes near the end of a momentous year for the park, city and college that share the name Gettysburg, as hundreds of thousands of visitors took part in historical re-enactments and ceremonies.

Lincoln’s Gettysburg Address — first delivered here nearly five months after the major battle that left tens of thousands of men wounded, dead or missing — will be read by a re-enactor to mark the anniversary. The ceremony will begin in the morning with a wreath laying event at the Soldiers’ National Cemetery. There also will be a graveside salute to U.S. Colored Troops at noon, and a tree planting ceremony in the afternoon.

U.S. Supreme Court Justice Antonin Scalia is to swear in 16 new American citizens and join Corbett a luncheon in honor of a high school girl who won a contest with her essay about the importance the Gettysburg Address, park officials said.

Some visitors are honoring the speech as well as the men who fought in the battle. Tom Stack, 54, of Wilmington, Del., has an ancestor who fought and died at Gettysburg while serving with the 1st Minnesota Volunteer Regiment.

“It was an incredible time, with incredible individuals, on both sides, really,” Stack said Monday.

The short oration, which begins, “Four score and seven years ago,” was intended to mark the dedication of the cemetery at the site of the pivotal battle. But it also came as Lincoln’s own reasons for fighting the Civil War were evolving. He spoke of how democracy itself rested upon “the proposition that all men are created equal,” a profound and politically risky statement for the time. Slavery and the doctrine of states’ rights would not hold in the “more perfect union” of Lincoln’s vision.

It was not immediately recognized as a towering literary achievement. Just last week, The Patriot-News in nearby Harrisburg retracted a dismissive editorial about the speech published by its Civil War-era predecessor, The Harrisburg Patriot & Union. The newspaper now says it regrets the error of not seeing its “momentous importance, timeless eloquence and lasting significance.”