Feb. 1, 2006: Exactly 15 years ago one of the most important masters of jiu-jitsu and MMA history was declared dead in a hospital in Chicago, putting the entire martial arts community in mourning. Carlson Gracie died due to heart failure as a result of complications of kidney stones following a hospitalization of several days.

https://www.sherdog.com/news/articles/Remembering-the-Impact-of-Carlson-Gracie-177514