Billy Peebles, headmaster of The Lovett School, studies history, and is fascinated by Abraham Lincoln.

Billy Peebles gets excited when he talks about Abraham Lincoln.

Peebles’ eyes light as he warms to his subject. He speaks quickly, jumping from topic to topic, enthusiasm building, as he recounts events from Lincoln’s life or discusses the 16th president’s writings.

“It’s just a great American story,” Peebles said one recent afternoon as he sat in his office at The Lovett School, where he has been headmaster for a decade.

“[Lincoln] becomes a respected lawyer. He’s sought out all over the Midwest. But his great love is not the law. It’s politics. The guy is a workhorse. He wrote all of his own speeches. He does all his own research. He did all his own edits.”

And, of course, Lincoln changed American history. He led the northern states to victory in the Civil War, a conflict that – partly through his words – remade the country and the way we think about it.

The war also changed Lincoln. The ways he changed are part of what interests Peebles.

Peebles studies history. In his first years as a teacher, he said, he started reading Lincoln’s writings. The young historian grew fascinated with the dead president’s thoughts about God and religion. “He had a very nuanced faith,” Peebles said.

On May 28, Peebles will present a public talk on Lincoln’s faith. His lecture, titled “Abraham Lincoln: How His Faith Shaped Policy,” is scheduled to begin at 7 p.m. at the Atlanta History Center, 130 West Paces Ferry Road, and is sponsored by the center and the Buckhead Heritage Society. Admission is free for members of either group, but tickets cost $15 for others.

This year has been sort of a “Year of Lincoln” in popular culture. Daniel Day-Lewis won an Oscar portraying Lincoln in a blockbuster movie. (“I thought it was great,” Peebles said of the movie.) The Emancipation Proclamation and the Gettysburg Address, two of Lincoln’s best-known statements of public policy, reach their 150th anniversaries this year, helping renew interest in writings and speeches by the self-taught frontier lawyer who became a focus of national debate over slavery.

“He was such an unusual character,” Peebles said. “He taught himself Euclidean geometry! He taught himself how to survey.”

And as Peebles sees it, Lincoln thought hard and deep about religion. Faith was important to him. “I think it helped to shape his character,” Peebles said. “I think it helped to shape some pretty significant policies.”

Growing up on the edge of the country, Lincoln “was steeped in the hard-shell, predestination, Baptist tradition,” Peebles said. “But he really rebelled against that. By the standards of his day, he was pretty eclectic.”

The war seems to have challenged Lincoln’s faith, Peebles said. At times, Lincoln appears to have been a skeptic, Peebles said, but, just weeks before the president’s assassination, he delivers his second inaugural address, which contains more than a half-dozen direct references to God.

In times of both war and peace, many politicians come to believe that God is on their side. Lincoln “never fell victim to that kind of self-righteousness,” Peebles said.

Instead, he articulated a belief that the Civil War “was so horrific because God was holding the whole country accountable for slavery,” Peebles said. Even the winners would lose.

As he discussed Lincoln’s thoughts, Peebles turned to the bookshelves lining a wall in his office at Lovett. They were filled with volumes on Lincoln and on the Civil War. He pulled down one book he had found particularly useful. The title: “Abraham Lincoln, from Skeptic to Prophet.” “That’s a great description, right there,” Peebles said.

In Lincoln’s writings, Peebles found a man “wrestling with himself” over religion and moral thinking as he tried to make sense of the horrors he saw all around him as the nation fought its Civil War.

“There’s a lot of self-reflection,” Peebles said. “That’s unusual for anybody, much less a president.”