Bernie Sanders said he is "proud to stand with" Hillary Clinton, while Michelle Obama said Clinton has "the guts and grace" to be president, as Democrats strove to appear unified at their national convention.

Sanders urged his supporters to back Clinton. He told the convention that "Hillary Clinton must become the next President of the United States." However, his supporters had arrived at the convention infuriated over leaked emails showing the Democratic National Committee had favoured Clinton in the primaries, despite vows of neutrality. They erupted in chants of "Bernie" and booed Clinton several times when her name was mentioned.

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Vermont Senator and former Democratic presidential candidate Bernie Sanders addresses delegates on Day 1 of the Democratic National Convention at the Wells Fargo Center in Philadelphia, PennsylvaniaAlex Wong/ Getty Images
Democratic National Convention 2016
Senator Bernie Sanders addresses delegates on the first day of the Democratic National Convention at the Wells Fargo Centre in PhiladelphiaChip Somodevilla/Getty Images
Democratic National Convention 2016
Senator Bernie Sanders addresses the Democratic National ConventionWin McNamee/Getty Images
Democratic National Convention 2016
Former Democratic presidential candidate Senator Bernie Sanders speaks at the Democratic National ConventionGary Cameron/Reuters
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Delegates show their support for Bernie Sanders at the Democratic National ConventionAFP/Getty Images
Democratic National Convention 2016
A supporter of former Democratic presidential candidate Bernie Sanders makes his way past delegates at the Democratic National ConventionMike Segar/Reuters
Democratic National Convention 2016
A supporter of Vermont Senator Bernie Sanders cries as the former Democratic presidential candidate addresses the Democratic National ConventionNicholas Kamm/AFP
Democratic National Convention 2016
A Bernie Sanders supporter with a fake bird on his shoulder is seen on the floor on Day One of the Democratic National ConventionTimothy A Clary/AFP
Democratic National Convention 2016
Senator Bernie Sanders walks off stage after delivering remarks on the first day of the Democratic National ConventionChip Somodevilla/Getty Images

Although Sanders couldn't quiet the shouts of his die-hard supporters, Michelle Obama could. She delivered a sharp attack on Trump — without ever mentioning his name. She said she wants to see elected "someone who understands that the issues a president faces are not black and white and cannot be boiled down to 140 characters." She lauded Clinton as a woman with a heart and as a future president who never "buckles under pressure" or takes the easy way out.

Democratic National Convention 2016
First lady Michelle Obama acknowledges the crowd before delivering remarks on the first day of the Democratic National ConventionAlex Wong/Getty Images
Democratic National Convention 2016
Delegates stand and cheer as first lady Michelle Obama addresses the Democratic National ConventionJoe Raedle/Getty Images
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Delegates listen to a speech on the first day of the Democratic National Convention at the Wells Fargo CentreChip Somodevilla/Getty Images

Other big names on the first night included Elizabeth Warren, who delivered the keynote address. "I'm with Hillary. This choice is personal. It's about who we are as a people," she said. Warren called Clinton "one of the smartest, toughest, most tenacious people on this planet," contrasting her decades-long record of public service with Trump, whom she described as a man who has never sacrificed anything for anyone. "Donald Trump has no real plans for jobs, for college kids, for seniors," she said. "No plans to make anything great for anyone except rich guys like Donald Trump," she said.

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Elizabeth Warren (D-MA) acknowledges the crowd as she walks on stage to deliver remarks on the first day of the Democratic National Convention at the Wells Fargo Center in Philadelphia, PennsylvaniaJoe Raedle/ Getty Images
Democratic National Convention 2016
Senator Elizabeth Warren speaks on the first day of the Democratic National ConventionWin McNamee/Getty Images

There were also big names from the entertainment world, including comedian Sarah Silverman, and musicians Demi Lovato and Paul Simon. Several speakers pleaded for peace between the Democratic factions. Silverman, a Sanders supporter, said she would support Clinton "with gusto" and admonished the Sanders fans. "To the 'Bernie or Bust' people, you're being ridiculous," she said, drawing a roar from the crowd and another round of competing cheers between Clinton and Sanders supporters.

Democratic National Convention 2016
Baltimore Mayor Stephanie Rawlings-Blake bangs the gavel, calling to order the first day of the Democratic National ConventionJoe Raedle/Getty Images
Democratic National Convention 2016
Sarah Silverman speaks during the first day of the Democratic National ConventionChip Somodevilla/Getty Images
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Singer-songwriter Paul Simon performs on stage during the first day of the Democratic National ConventionJoe Raedle/Getty Images
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Delegates dance as Paul Simon sings during Day One of the Democratic National ConventionTimothy A Clary/AFP
Democratic National Convention 2016
Delegates and attendees stand and cheer as singer-songwriter Paul Simon performs on stage during the first day of the Democratic National ConventionJoe Raedle/Getty Images
Democratic National Convention 2016
Delegates dance at the Democratic National Convention in PhiladelphiaJim Young/Reuters
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Demi Lovato performs on Day One of the Democratic National ConventionBrendan Smialowski/AFP
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Senator Cory Booker reacts after actress Eva Longoria introduced him on the first day of the Democratic National ConventionAaron P Bernstein/Getty Images
Democratic National Convention 2016
Boyz II Men performs on stage during the opening of the first day of the Democratic National ConventionChip Somodevilla/Getty Images
Democratic National Convention 2016
A delegate hoisting a sign stands in the spotlight on the floor on Day One of the Democratic National ConventionBrendan Smialowski/AFP
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Former President Bill Clinton shakes hands with Nancy Pelosi during Day One of the Democratic National ConventionRobyn Beck/AFP
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Senator Cory Booker speaks with former US President Bill Clinton during the first day of the Democratic National ConventionWin McNamee/Getty Images
Democratic National Convention 2016
Senator Cory Booker speaks at the Democratic National ConventionMike Segar/Reuters
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Jason and Jarron Collins, twin brothers and former professional basketball players, arrive on stage during Day One of the Democratic National ConventionSaul Loeb/AFP
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Wisconsin delegate Angie Aker wears tape over her mouthChip Somodevilla/Getty Images
Democratic National Convention 2016
Delegates from Michigan wear tape over their mouths reading 'Silenced By DNC' on the first day of the Democratic National ConventionChip Somodevilla/Getty Images
Democratic National Convention 2016
An attendee wears a hat with campaign memorabilia prior to the start of the first day of the Democratic National ConventionChip Somodevilla/Getty Images
Democratic National Convention 2016
Various hats are worn by delegates at the Democratic National ConventionReuters/Getty Images
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A delegate wears a jacket with an image of Democratic presidential candidate Hillary ClintonJoe Raedle/Getty Images
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A delegate wears Bernie Sanders glasses on the first day of the Democratic National ConventionChip Somodevilla/Getty Images
Democratic National Convention 2016
An all-gender toilet sign is posted on the first day of the Democratic National Convention at the Wells Fargo Centre in PhiladelphiaWin McNamee/Getty Images
Democratic National Convention 2016
Red, white and blue balloons hang in the rafters at the Wells Fargo CentreAaron P Bernstein/Getty Images

Trump gloated at the Democrats' opening day disorder. "Wow, the Republican Convention went so smoothly compared to the Dems total mess," he tweeted.