The mayhem happened early Sunday at a hotel in the Society Hill neighborhood. Witnesses watched police try to control the crowd of at least 75 with batons and Tasers.
The 57-year-old uncle of one bride suffered a fatal heart attack outside the reception, but police don't know if he was involved in any of the fights.
The fight was caught on camera and posted on YouTube by Max Schultz, 15. He was staying at the hotel with his family for his birthday and used his phone to take the video, capturing dozens of people in tuxedos and ball gowns fighting before police arrived.
Police aren't sure what started the brawl, but they say alcohol was involved.
The Associated Press contributed to this report.
