When George Washington took the oath of office as the country's first president in 1789, he placed his hand upon the Bible while speaking those solemn 35 words required by the Constitution, beginning a tradition that has come to define the pomp and circumstance of Inauguration Day.
And though the act of swearing upon a Bible held significance at the time, the particular book he chose did not.
It was, historians say, an afterthought. Organizers had simply forgotten to bring one, so they grabbed the closest Holy book they could find - a nearby Masonic lodge's altar Bible - and Washington made his promise.
But in the two centuries since then, the act of choosing an inaugural Bible - or Bibles - has become far more symbolic.
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Franklin Delano Roosevelt used his family's Bible, written in Dutch and printed in 1686. John F. Kennedy, the first Catholic elected to the White House, chose a Douay Bible. And when his second inauguration fell on Martin Luther King, Jr. Day, President Barack Obama chose to lay his hand upon a book of Holy Scripture that belonged to the civil rights leader.
The story behind the Bible adds gravitas - and gives media commentators something to talk about.
On Wednesday, President-elect Donald Trump announced his choices: a Bible his mother gifted him in 1955 when he graduated from Presbyterian Sunday school and the one President Abraham Lincoln used at his inauguration.
In a statement, Presidential Inauguration Committee Chairman Tom Barrack explained the selections.
"In his first inaugural address, President Lincoln appealed to the 'better angels of our nature,' " Barrack said. "As he takes the same oath of office 156 years later, President-elect Trump is humbled to place his hand on Bibles that hold special meaning both to his family and to our country."
Trump's choices seem to make a nod to themes that deeply defined his controversial campaign for the presidency and the direction of his administration since emerging victorious - religion and race, and his complicated relationship with both.
The last, and only other president since Lincoln, to use the Lincoln Bible was Obama, both in 2009 and 2013, a choice the 44th president said was meant to emphasize Lincoln's call for "national unity" during his first inaugural address. Others speculated that Obama's selection evoked even deeper symbolism - the first black president taking the oath on the Bible of the Great Emancipator.
But the connection to Lincoln's Bible is less obvious for Trump. Lincoln was, after all, a man credited with keeping America from permanently fracturing during the Civil War. Trump won the presidency on a campaign fraught with division.
And the President-elect's relationship with the African American community has thus far been strained - especially this week after Trump fired off an insulting and erroneous tweet about Rep. John Lewis, D-Ga., the civil rights giant who said he believes that reports of Russian influence in the election made Trump "illegitimate" and pledged to boycott the inauguration. Since then, nearly 60 other House Democrats have joined him.
Trump has spoken about Lincoln before.
In an interview with The Washington Post, reporter Bob Woodward asked Trump, then a candidate, what made Lincoln successful. His response:
"Well, I think Lincoln succeeded for numerous reasons. He was a man who was of great intelligence, which most presidents would be. But he was a man of great intelligence, but he was also a man that did something that was a very vital thing to do at that time. Ten years before or 20 years before, what he was doing would never have even been thought possible. So he did something that was a very important thing to do, and especially at that time."
Trump spoke of Lincoln during a debate last October, when Democratic candidate Hillary Clinton tried to explain away some of her closed-door comments to the business community revealed through WikiLeaks with a reference to Steven Spielberg's movie "Lincoln."
"Now she's blaming the lie on the late, great Abraham Lincoln. That's one that I haven't . . ." Trump said during the debate. "OK, Honest Abe, Honest Abe never lied. That's the good thing. That's the big difference between Abraham Lincoln and you. That's a big, big difference."
And, perhaps coincidentally, the very passage from Lincoln's first inaugural address, appealing to the "better angels of our nature," that Trump's team cited in its Bible announcement was actually tweeted at the president-elect earlier this month - by Arnold Schwarzenegger.
Trump had tweeted negatively at the former California governor and current Apprentice host about his ratings on the reality TV show, saying Schwarzenegger got "'swamped' (or destroyed) by comparison to the ratings machine, DJT."
Schwarzenegger responded with a video of himself reading aloud that noteworthy passage from Lincoln's address and asked Trump to "please study" it.
The president-elect's second Bible selection references his Presbyterian upbringing in Jamaica, Queens, in New York City. His mother gave it to him on June 12, 1955, upon his graduation from Sunday Church Primary School at First Presbyterian Church on Children's Day.
"The Bible is a revised standard version published by Thomas Nelson and Sons in New York in 1953 and is embossed with his name on the lower portion of the front cover," Barrack said in a statement. "The inside cover is signed by church officials and is inscribed with his name and the details of when it was presented."
Trump's faith history was an early point of contention with evangelicals during the campaign, but come election day, they turned out in droves to vote for the Republican candidate. The selection of Vice President-elect Mike Pence - a devout Christian - may have helped boost support among that cohort, and Trump's team worked hard to appeal to the party's religiously conservative base.
In one such attempt, Trump thanked evangelical Christians for their support, said all the polls showed he was in their favor, then held up the Bible his mother gave him more than 50 years ago.
But since his election, some in the faith community have sought to distance themselves from the president-elect, particularly during traditionally religious elements of the inauguration, including an interfaith prayer service at Washington National Cathedral on Jan. 21, and it is unknown if any churches are planning to bus in congregants for the swearing in ceremony, a road trip made by many during the Obama years, The Post's Julie Zauzmer wrote last week.
Trump has called the Bible his favorite book - and 'The Art of the Deal' his second favorite - and told CBN News in 2011 that he hosts a Bible collection in "a very nice place" because so many people mail him copies of it.
"There's no way I would ever throw anything, to do anything negative to a Bible, so what we do is we keep all of the Bibles," Trump said at the time. "I would have a fear of doing something other than very positive so actually I store them and keep them and sometimes give them away to other people but I do get sent a lot of Bibles and I like that. I think that's great."
Being religious, or using a Bible to swear the oath of office, isn't required of American presidents. Most do, but some haven't, including John Quincy Adams, who took the oath on a law book.
Chief Justice John G. Roberts Jr. will administer the oath to Trump, who did not say in his statement whether either of the Bibles will be open to a particular passage, as is often done during the swearing in ceremony.
Pence will be sworn in by Supreme Court Associate Justice Clarence Thomas, the first African American to administer the oath of office to a vice president or president.
In his own statement, Pence announced that he will used the Reagan family Bible - used by President Ronald Reagan during his gubernatorial and presidential inaugurations. It will be the first time the Reagan Bible has been used to take the oath since.
And unlike Trump, Pence has planned to open the book to the same passage Reagan used, and one the vice president-elect often referenced on the campaign trail:
"If my people, which are called by my name, shall humble themselves, and pray, and seek my face, and turn from their wicked ways; then will I hear from heaven, and will forgive their sin, and will heal their land." (II Chronicles 7:14)