The anticipated swearing in ceremony for Joseph Robinette Biden Jr. as the 46th president of the United States has taken place on Wednesday.

Biden took office at a moment of profound economic, health and political crises with a promise to seek unity after a tumultuous four years that tore at the fabric of American society.

With his hand on a five-inch-thick Bible that has been in his family for 128 years, Mr. Biden recited the 35-word oath of office swearing to “preserve, protect and defend the Constitution” in a ceremony administered by Chief Justice John G. Roberts Jr., completing the process at 11:49 a.m., 11 minutes before the authority of the presidency formally changes hands.