When U.S. President Barack Obama took the oath of office Monday, he placed his hand on two Bibles.
The first was the Bible used by former President Abraham Lincoln, the 16th president of the United States, when he took the oath for his first term in 1861. The second Bible was the so-called "traveling Bible" used by slain civil rights leader Martin Luther King, Junior.
Monday is the official government holiday honoring King who was assassinated in 1968.
President Obama was officially sworn-in for a second term Sunday during a brief, private ceremony at the White House, where he used his wife Michelle's family Bible. Mr. Obama repeated the oath for the public Monday, where he also made his inaugural address.
The presidential term ends on the Constitutionally-mandated date of January 20, which was on a Sunday this year when courts and public offices are closed. Tradition holds that when Inauguration Day is on a Sunday, the president is sworn-in privately and a public ceremony is held the next day.
Monday's swearing-in was the fourth time Mr. Obama took the oath of office.
He was sworn-in twice for his first term in 2009 when the chief justice of the U.S. Supreme Court, John Roberts, stumbled over one of the words while administering the oath. So the oath was given again one day later.
Mr. Obama is the first president since Franklin Roosevelt to take the oath of office four times. Mr. Roosevelt was elected four times, in 1932, 1936, 1940, and 1944. The law currently limits a U.S. president to two four-year terms.
Also Sunday, Vice President Joe Biden took the oath of office on a Bible that his family has used since 1893.