The sanctuary of Zeus at Olympia had been a cult site with dedications there dating back to the tenth century BC, but the eighth century saw an explosion in the number of dedications: 160 animal figurines are known from the 9th century, compared to 1,461 from the 8th. Bronze tripods and jewellery have also been discovered as dedications at archaic Olympia. Though most of the dedications from the 8th century were manufactured in the Peloponnese, dedications also came from Attica, and even as far afield as Italy and the eastern Mediterranean.
This enormous explosion in cultic activity in Olympia apparently coincides with the establishment of the Olympic Games as a major event. According to Greek tradition the first games at Olympia had been established by Herakles, but these had fallen out of practice until they were revived in 776 BC.
Source: Wikipedia