Police had to use force to get things under control, and one man died of a heart attack while trying to leave the hotel.
Witness video showed the scene around 2:00 a.m. as dozens of Philadelphia police officers worked to control the violent clash between the two parties in the hotel bar.
Detectives say two relatives, possibly brothers, from one party got into an argument and somehow people from a second wedding party were pulled into it.
Police say the fight fueled by alcohol and rising tempers took over the bar and lobby.
Hotel guest Max Schultz, who Action News spoke to from his home outside Harrisburg, recorded the chaos and posted it to YouTube.
"It was very crazy, obviously, but I felt kind of safe with the huge police presence there," Schultz said.
The department says officers were outnumbered so they whipped out their batons and started swinging at those who resisted.
In the video, an officer can be seen trying to hold back one of the brides while a man in a tux is being thrown to the floor.
"I just thought it was very sad because it's suppose to be a special occasion and for something like that to happen, I just felt bad for the families," hotel guest Chris Himes said.
And it gets worse.
Investigators say a 57-year-old man stepped out of the hotel to get away from the melee when he had a heart attack on the street and died.
A family member told Action News the man wasn't part of the brawl or either wedding party.
The name of the man who died outside has not been released.
Sheraton Society Hill told Action News to direct our questions to police and would only say, "Our sincerest condolences go out to the family for their loss."
Police say two people were given summary citations and released.
A third man who was Tasered is in custody and will be charged with assault on a police officer.
The department says, after top police brass including Commissioner Charles Ramsey watched the video, they concluded that appropriate force was used to get things under control.
Schultz was in town with his parents celebrating his now very memorable 15th birthday.
"It's sad that this had to happen and I know what alcohol can do to people and it's a good example," Schultz said.
Our sister station, WPVI-TV in Philadelphia, is following the latest developments.