The Olympics first dated to 776BC and were held every 4 years.
They started in Olympia and were dedicated to the Olympian Gods in honour of Zeus (King of Gods) as a religious festival.
In the early games athletes were all male and lived in the city-states of Greece. They competed naked, therefore no women could compete on the pretext of being a man.
Only free male citizens were allowed to attend the games.
The Olympic Games started as a one-day event but grew over time to 5 days.
Originally there was only one event, a footrace (Stadion) in which men competed.
Over the years other events were added including a longer footrace (Diaulos) which was added in 724BC.
A 3 mile (5 kilometre) footrace (Dolichos) added in 720BC.
Wrestling added in 708BC.
In 648BC a mixture of events (Pankration) was competed in. This included Boxing, Wrestling, Kicking, Holds, Locks and Chokes.
Hoplite race (Hoplitodromos) in which competitors wore armour added in 520BC.
Other events were competed in including Chariot Racing and the Pentathlon, which included Wrestling, Footrace, Long Jump, Javelin throw and Discus throw.
When the games grew to 5 days, there were 3 days of competition and 2 days of religious festivals.
On the first day of the games, 700 oxen were sacrificed to Zeus, followed by 3 days of competition and a banquet on the final day. The sacrificed oxen became the basis of the banquet on the final day.