The Ancient Olympics started in Olympia, Greece in 776 BC, and they were held in recognition of the Olympian gods. The games were banned in 393 AD after they had been held for about 12 centuries. Since that time, the Modern Olympics were started in 1896. You can find more information here: http://www.olympic.org/en/content/Olympic-Games/Ancient-Olympic-Games/
The Olympics started in ancient Greece but the games were alot more violent then. Lots of participants died-killed by other participants or animals such as lions. A whole nother outlook on blood sports.
In Olympia, Greece the Olympic Games where held every four years. The first Olympic Game was took place about 3,000 years ago. At that time this great festival to honour the Greek gods. The Olympics where held to please the various gods. One God in particular the most important one was called Zeus.