The Greek Olympics was held every 4 years, it started in 776 B.C.
The Olympics were 1 week-long festival with many events. The Olympics were held in Olympia because that is where they thought all their gods lived.
All of Greece will go to Olympia and compete and there is something called “Olympic truth”, is where if 2 cities in Greece were fighting and having a war together which is very often, they would just stop arguing and have fun.
The very first Olympics only had 1 event, a foot race, but there were more events afterwards.