WASHINGTON — Joe Biden was sworn in as the 46th president of the United States on Wednesday, declaring that “democracy has prevailed” and summoning American resilience and unity to confront the deeply divided nation’s historic confluence of crises.

Biden took the oath at a U.S. Capitol that had been battered by an insurrectionist siege just two weeks earlier. On a cold Washington morning dotted with snow flurries, the quadrennial ceremony unfolded within a circle of security forces evocative of a war zone and devoid of crowds because of the coronavirus pandemic.

Instead, Biden gazed out over 200,000 American flags planted on the National Mall to symbolize those who could not attend in person.

“The will of the people has been heard, and the will of the people has been heeded. We’ve learned again that democracy is precious and democracy is fragile. At this hour, my friends, democracy has prevailed,” Biden said. “This is America’s day. This is democracy’s day. A day in history and hope, of renewal and resolve.”

History was made at his side, as Kamala Harris became the first woman to be vice president. The former U.S. senator from California is also the first Black person and the first person of South Asian descent elected to the vice presidency and the highest-ranking woman ever to serve in the U.S. government.

Biden never mentioned his predecessor, who defied tradition and left town ahead of the ceremony.

“We have much to do in this winter of peril, and significant possibilities. Much to repair, much to restore, much to heal, much to build and much to gain,” Biden said. “Few people in our nation’s history have been more challenged, or found a time more challenging or difficult than the time we’re in now.”

Biden was eager to go big early, with an ambitious first 100 days including a push to speed up the distribution of COVID-19 vaccinations to anxious Americans and pass a $1.9 trillion economic relief package. On Day One, as part of a push to roll back Trump administration initiatives, he signed a series of executive actions, including to reenter the Paris Climate Accords and to mandate mask wearing on federal property.

“There’s no time to start like today,” Biden said as he signed the actions in the Oval Office.

The absence of Biden’s predecessor from the inaugural ceremony underscored the national rift to be healed.

But a bipartisan trio of former presidents — Bill Clinton, George W. Bush and Barack Obama — were there to witness the ceremonial transfer of power. Trump, awaiting his second impeachment trial, was at his Florida resort by the time the swearing-in took place.

Swearing the oath with his hand on a five-inch-thick Bible that has been in his family for 128 years, Biden came to office with a well of empathy and resolve born by personal tragedy as well as a depth of experience forged from more than four decades in Washington. At age 78, he is the oldest president inaugurated.

Both he, Harris and their spouses walked the last short part of the route to the White House after an abridged parade. Biden then strode into the Oval Office, a room he knew well as vice president, for the first time as commander in chief.

Earlier, the two were sworn in during an inauguration ceremony with few parallels. Biden, like all those in attendance, wore a face mask except when speaking. And tens of thousands of National Guard troops were on the streets to provide security precisely two weeks after a violent mob of Trump supporters, incited by the Republican president, stormed the Capitol in an attempt to prevent the certification of Biden’s victory.

“Here we stand, just days after a riotous mob thought they could use violence to silence the will of the people,” Biden said. “To stop the work of our democracy. To drive us from this sacred ground. It did not happen. It will never happen. Not today, not tomorrow. Not ever. Not ever.”

The tense atmosphere evoked the 1861 inauguration of Abraham Lincoln, who was secretly transported to Washington to avoid assassins on the eve of the Civil War, or Franklin Roosevelt’s inaugural in 1945, when he opted for a small, secure ceremony at the White House in the waning months of World War II.

But Washington, all but deserted downtown and in its federal areas, was quiet. And calm also prevailed outside heavily fortified state Capitol buildings across nation after the FBI had warned of the possibility for armed demonstrations leading up to the inauguration.

The day began with a reach across the political aisle after four years of bitter partisan battles under Trump. At Biden’s invitation, congressional leaders from both parties bowed their heads in prayer in the socially distanced service a few blocks from the White House.

Biden was sworn in by Chief Justice John Roberts; Harris by Justice Sonia Sotomayor, the first Latina member of the Supreme Court. Vice President Mike Pence, standing in for Trump, sat nearby as Lady Gaga, holding a golden microphone, sang the National Anthem accompanied by the U.S. Marine Corps band.

When Pence, in a last act of the outgoing administration, left the Capitol, he walked through a door with badly cracked glass from the riot two weeks ago. Later, Biden, Harris and their spouses were joined by the former presidents to solemnly lay a wreath at the Tomb of the Unknown Soldier at Arlington National Ceremony.

Biden was also to join the end of a slimmed-down inaugural parade as he moves into the White House. Because of the pandemic, much of this year’s parade was to be a virtual affair featuring performances from around the nation.

In the evening, in lieu of the traditional balls that welcome a new president to Washington, Biden was to take part in a televised concert that also marked the return of A-list celebrities to the White House orbit after they largely eschewed Trump. Among those in the lineup: Bruce Springsteen, Justin Timberlake and Lin-Manuel Miranda.