Wrestling was one of the original sports at the first ancient Olympics and dates back further still.
There is evidence of wrestling having taken place in Egypt as much as 5,000 years ago.
Greco-Roman wrestling was included in the first modern Olympics back in 1896, but did not reappear until 1908, since when it has been present at every games. Freestyle made its Olympic debut in 1904.
Women's freestyle wrestling was included in the Olympics for the first time in 2004. At the same time, the number of men's weight categories was reduced from 16 to 14.
Traditional strongholds of wrestling include eastern Europe and the United States, where collegiate wrestling, similar to freestyle, is a staple in high schools and colleges.
Former WWE star Kurt Angle won a gold in the men's freestyle in Atlanta in 1996.
Wang Xu of China won the debut women's heavyweight freestyle event in 2004.
There are 337 wrestlers representing 57 countries competing for 18 gold medals.
RESULTS FROM OLYMPICS IN ATHENS IN 2004
Wrestling Men's Freestyle 55 kg (finals)
1 Mavlet Batirov (RUSSIA)
2 Stephen Abas (USA)
3 Chikara Tanabe (JAPAN)
Wrestling Men's Freestyle 60 kg (finals)
1 Yandro Miguel Quintana (CUBA)
2 Masuod Jokar (IRAN)
3 Kenji Inoue (JAPAN)
Wrestling Men's Freestyle 66 kg (finals)
1 Elbrus Tedeyev (UKRAINE)
2 Jamill Kelly (USA)
3 Makhach Murtazaliev (RUSSIA)
Wrestling Men's Freestyle 74 kg (finals)
1 Buvaysa Saytiev (RUSSIA)
2 Gennadiy Laliyev (KAZAKHSTAN)
3 Ivan Fundora (CUBA)
Wrestling Men's Freestyle 84 kg (finals)
1 Cael Sanderson (USA)
2 Eui Jae Moon (SOUTH KOREA)
3 Sazhid Sazhidov (RUSSIA)
Wrestling Men's Freestyle 96 kg (finals)
1 Khadjimourat Gatsalov (RUSSIA)
2 Magomed Ibragimov (UZBEKISTAN)
3 Alireza Heidari (IRAN)
Wrestling Men's Freestyle 120 kg (finals)
1 Artur Taymazov (UZBEKISTAN)
2 Alireza Rezaaei (IRAN)
3 Aydin Polatci (TURKEY)
Wrestling Men's Greco-Roman 55 kg (finals)
1 Istvan Majoros (HUNGARY)
2 Gueidar Mamedaliev (RUSSIA)
3 Artiom Kiouregkian (GREECE)
Wrestling Men's Greco-Roman 60 kg (finals)
1 Ji Hyun Jung (SOUTH KOREA)
2 Roberto Monzon (CUBA)
3 Armen Nazarian (BULGARIA)
Wrestling Men's Greco-Roman 66 kg (finals)
1 Farid Mansurov (AZERBAIJAN)
2 Seref Eroglu (TURKEY)
3 Mkkhitar Manukyan (KAZAKHSTAN)
Wrestling Men's Greco-Roman 74 kg (finals)
1 Alexandr Dokturishivili (UZBEKISTAN)
2 Marko Yli-Hannuksela (FINLAND)
3 Varteres Samourgachev (RUSSIA)
Wrestling Men's Greco-Roman 84 kg (finals)
1 Alexei Michine (RUSSIA)
2 Ara Abrahamian (SWEDEN)
3 Viachaslau Makaranka (BELARUS)
Wrestling Men's Greco-Roman 96 kg (finals)
1 Karam Ibrahim (EGYPT)
2 Ramaz Nozadze (GEORGIA)
3 Mehmet Ozal (TURKEY)
Wrestling Men's Greco-Roman 120 kg (finals)
1 Khasan Baroev (RUSSIA)
2 Georgiy Tsurtsumia (KAZAKHSTAN)
3 Rulon Gardner (USA)
Wrestling Women's Freestyle 48 kg (finals)
1 Irini Merleni (UKRAINE)
2 Chiharu Icho (JAPAN)
3 Patricia Miranda (USA)
Wrestling Women's Freestyle 55 kg (finals)
1 Saori Yoshida (JAPAN)
2 Tonya Verbeek (CANADA)
3 Anna Gomis (FRANCE)
Wrestling Women's Freestyle 63 kg (finals)
1 Kaori Icho (JAPAN)
2 Sara McMann (USA)
3 Lise Legrand (FRANCE)
Wrestling Women's Freestyle 72 kg (finals)
1 Xu Wang (CHINA)
2 Gouzel Maniourova (RUSSIA)
3 Kyoko Hamaguchi (JAPAN)
