Barack Obama, left, joined by his wife Michelle, second from left, and daughters Sasha, third from left, and Malia, takes the oath of office from Chief Justice John Roberts to become the 44th president of the United States at the U.S. Capitol in Washington, Tuesday, Jan. 20, 2009.

Barack Hussein Obama has taken the oath of office as the 44th president of the United States.

With a hand on Abraham Lincoln’s inaugural bible, and before a crowd stretching across the National Mall toward where Martin Luther King Jr. spoke of his dream of racial equality, the 47-year-old Obama was sworn in as the first black American president by Chief Justice John Roberts.

Roberts told him, “Congratulations, Mr. President.”

Obama’s wife, Michelle, and young daughters Sasha and Malia looked on. They were joined by people from around the world who gathered in huge numbers in the early morning Washington cold to see history made.