Joseph Robinette Biden Jr., the former vice president and twice previously a failed candidate for the presidency, was declared the 46th president of the United States on Saturday, after four days of electoral uncertainty, back-and-forth lead changes in almost a dozen key states, protests at election offices in Michigan and Arizona, and continuing threats of legal action by the incumbent president, Donald J. Trump.

The race was called by the Associated Press on Saturday at around 11:30, when the 20 Electoral College votes from Pennsylvania pushed Biden across the 270-vote finish line. It was an extraordinary turn of events, as Trump started the week with a huge edge in same-day Election Day voting in Pennsylvania, one that Biden gradually and decisively chipped away at as the advance ballots were counted over the next four days. At about 9 a.m. on Friday, a new batch of votes from Philadelphia were announced—advance voting in that city had been going for Biden by roughly 90% to 10% over Trump—giving Biden a 5,000 vote lead in Pennsylvania, the first since election results had begun to reported three days earlier. Biden also led in three states that had not yet been officially called—Georgia, Nevada, and Arizona—but the Pennsylvania results gave Biden a lead that Trump was now incapable of overcoming.

Biden, who will turn 78 later this month, will be the oldest man ever to be inaugurated as president when he takes the oath of office on January 20, 2021. Biden’s running mate, California senator Kamala Harris, born of immigrant parents from India and Jamaica, becomes the first woman ever elected to the vice presidency, achieving a goal that eluded Geraldine Ferraro in 1984 and Sarah Palin in 2008. She also becomes the first Black woman to be elected to national office.

President Trump—who began his presidency by talking about “American carnage” and exaggerating the size of his inaugural crowd, and then spent most of 2020 denying the seriousness of the coronavirus pandemic—is the first incumbent president not to be elected to a second term since George H.W. Bush in 1992.

This was an election week like no other. In the early morning hours of Wednesday, President Trump took the startling position of declaring that—based on the same-day vote already recorded—he had won the presidency and would mount a legal challenge if the final tally did not go his way. “Millions and millions of people voted for us,” Trump said in a mask-free gathering in the East Room of the White House. “And a very sad group of people is trying to disenfranchise that group of people.” Added Trump: “So we’ll be going to the Supreme Court.… We will win this, and as far as I’m concerned, we already have.”