Politicians, military leaders and celebrities from across the US have paid farewell to former Delaware attorney general Beau Biden, whose death at age 46 opened yet another chapter of grief for his father, vice president Joe Biden.
Calling himself part of the Biden clan, President Barack Obama remembered Beau Biden as a selfless son and consummate public servant in a eulogy delivered at his funeral service.
"He did in 46 years what most of us couldn't do in 146," Mr Obama said. "He left nothing in the tank."
Addressing the vice president and his wife Jill, Mr Obama reflected on their friendship: "Michelle and I thank God you are in our lives. Taking this ride with you is one of the great pleasures of our lives. Joe, you are my brother."
Beau Biden, the vice president's oldest son, died a week ago after a two-year battle with brain cancer that played out mostly in private, in contrast to the intensely public life that the Bidens have lived for decades.
An overflow crowd of more than 1,000 packed St Anthony of Padua Catholic Church in Wilmington, Delaware, to pay their respects.
Local residents sat among political luminaries such as Hillary Rodham Clinton, former president Bill Clinton and attorney general Loretta Lynch.
For the vice president, the death marked yet another untimely personal loss. More than four decades ago a car crash killed his wife and baby daughter and injured his two sons just weeks after he was elected to the Senate.
Joe Biden was sworn in at the hospital where three-year-old Beau and his younger brother, Hunter, were being treated.
The vice president, who did not speak at the funeral, embraced Mr Obama after crossing himself solemnly as he entered the church to the strains of Bring Him Home, from the musical Les Miserables.
Outside the church before the Mass of Christian Burial, Joe Biden held hands with his son's widow, Hallie Biden, and his granddaughter, Natalie, as six pallbearers wheeled the coffin into the church.
Amid the solemnity were spirited moments - a gospel choir's rendition of Amazing Grace and Coldplay lead singer Chris Martin's performance of Till Kingdom Come. The White House said Hunter Biden had been a Coldplay fan and that when Martin found out, he asked to come to the funeral.
General Ray Odierno, who was the top US commander in Iraq when Beau Biden served there, eulogised his former soldier and presented him with the Legion of Merit, which honours U.S. service members for exceptionally meritorious conduct.
Beau Biden's role as the celebrated scion of the vice president's family was reflected time and again in the remarks of his siblings, Hunter and Ashley - Joe Biden's two surviving children.
Ashley Biden recalled accompanying her brother to his chemotherapy treatments and said she would forever cherish the time she had spent with him on those Fridays over breakfast.
"He was our protector, our mediator, the captain of our lives," she said.
The funeral for Beau Biden, who died at Walter Reed National Military Medical Center outside Washington, capped three days of public mourning in which the vice president and his family were both the consolers and the consoled.
His casket lay in honour in the state Senate chamber on Thursday ahead of a public viewing on Friday. On both days, seemingly endless lines of people streamed through to greet the vice president, whose sadness at times gave way to his characteristic humanity as he greeted familiar faces with a broad smile, a lingering hug or a fond memory of his son.
Beau Biden served two terms as attorney general before declaring a run for governor, and many saw in him the same aspirations that brought his father to the vice presidency after several unsuccessful presidential bids.
But in 2010, at age 41, he suffered a stroke, then was diagnosed with brain cancer three years later. He returned to work after treatment, but the cancer returned.
Hunter Biden, 45, said his earliest memory was of lying next to his brother in the hospital, with Beau Biden holding his hand and repeating: "I love you."
"And as it began, so did it end," Hunter Biden said, recalling his brother's final moments in the hospital surrounded by family.
"Each of us desperately, desperately holding him. Each of us whispering, 'I love you, I love you, I love you.' I held his hand, and he took his last breath, and I know that I was loved."