President Joe Biden has enjoyed a long career in public life since becoming the sixth-youngest senator in the history of the United States when he was first elected in 1972.
After several Senate re-elections and after an already distinguished political career, he was thrust into the spotlight as a popular vice-president in the Obama administration in 2009 and has since been a household name in the US.
But away from his privileged public life, Biden has endured many private tragedies.
Biden was a happily married family man when he was elected a senator in the 1970s. He had married Neilia Hunter in 1966, and the couple had three children: Joseph (known as Beau), Robert (known as Hunter), and Naomi.
Just a few weeks after he was elected in 1972, Biden's wife Neilia and their three children were returning home from Christmas shopping in Delaware when their car was hit by a tractor trailer at an intersection.
Neilia and Naomi, 1, were killed. Beau and Hunter were taken to hospital. Beau, 3, had a broken leg and Hunter, 4, had a skull fracture.
Biden gave some consideration to resigning so that he would be in a better position to provide care for his sons, but colleagues convinced him to continue in politics, and he was sworn in as a senator at Beau's hospital bedside in early 1973.
LIVING WITH GRIEF
Biden was deeply affected by the accident that killed two members of his family and has openly acknowledged the difficulty and grief he faced in the years that followed.
In his book Promises to Keep, Biden describes the anger and confusion he felt, and the crisis of faith he suffered.
"I had not known I was capable of such rage... I felt God had played a horrible trick on me," he wrote.
Determined to care for his sons, Biden travelled an hour-and-a-half each way from the family home to Washington DC so that he could continue to see his sons and care for them while he worked as a senator.
Five years after the car accident, Biden married for a second time, to Jill Jacobs. In 1981 they welcomed a daughter, Ashley, their only child together.
Jill Biden spoke movingly about her husband's grief during her address to the Democratic National Convention.
"I fell in love with a man and two little boys standing in the wreckage of unthinkable loss. Mourning a wife and mother; a daughter and sister. I never imagined, at the age of 26, I would be asking myself, 'How do you make a broken family whole?'" she said.
"Still, Joe always told the boys, 'Mummy sent Jill to us.' And how could I argue with her? And so we figured it out together.
"How do you make a broken family whole? The same way you make a nation whole. With love and understanding, and with small acts of kindness.
"You show up for each other, in big ways and small ways, again and again."
ANOTHER CRUSHING LOSS
In 2015, Biden's eldest child, Beau, died from brain cancer at 46.
Beau had a distinguished career as Delaware's state attorney-general, and had spent time in Iraq as an army judge advocate.
After Beau's death, Biden became focused on the importance of cancer research and led the Cancer Moonshot programme within the Obama administration.
Not long after losing his son, the then-vice president opened up about his grief during an interview with late night TV host Stephen Colbert, and the role of his faith.
"I was a hell of a success; my son was better than me. He was better than me in every way," Biden said.
"For me, my religion is just an enormous sense of solace.
"Some of it relates to ritual, some of it relates to just comfort, in what you've done your whole life. I go to mass and I'm able to be just alone, even in a crowd. You're alone.
"What my faith has done is, it sort of takes everything about my life, with my parents and my siblings and all the comforting things, and all the good things that have happened have happened around the culture of my religion.
"I don't know how to explain it more than that. It's just a place you can go."
He cited a quote by Danish philosopher Soren Kierkegaard: "Faith sees best in the dark."
Jill Biden also addressed Beau's death during her convention speech.
"After our son Beau died of cancer, I wondered if I would ever smile or feel joy again. It was summer, but there was no warmth left for me," she said.
"Four days after Beau's funeral, I watched Joe shave and put on his suit. I saw him steel himself in the mirror, take a breath, put his shoulders back, and walk out into a world empty of our son.
"He went back to work. That's just who he is. There are times when I couldn't even imagine how he did it, how he put one foot in front of the other and kept going.
"But I've always understood why he did it."
THE POWER OF EMPATHY
Biden's empathy, forged by the personal tragedies he has faced, is considered to be one of his great strengths.
"Joe Biden has an almost superpower," Delaware Senator Chris Coons told Politico in 2019, "in his ability to comfort and listen and connect with people who have just suffered the greatest loss of their lives".
Perhaps the most powerful moment of Biden's presidential campaign this year came during his victory speech in the South Carolina primary.
He spoke movingly about Beau's death, and how the people of South Carolina had helped them heal.
When the Bidens visited the state in 2015, it was mourning its own tragedy – the Charleston church massacre, which left nine people dead.
They were struck by the strength of those who had lost their loved ones in the shooting.
"Through all that pain, all that grief, they forgave," Biden told the crowd after his primary win.
"Six weeks earlier, we had lost our son Beau. And we needed to be healed too. We needed to be healed. I really mean this.
"We needed whatever they were exuding. And with every season that's passed, they've gotten up and found purpose to live life worthy of the ones they lost. Worthy of the blessing to live in this remarkable country.
"We left here, having arrived in overwhelming pain, thinking we can do this. We can get through this.
"It's no small reason why I'm in this race. People like all of you here tonight, all around the country. The days of Donald Trump's divisiveness will soon be over."