From the day of its birth, sports was closely related to religion, In addition, in the ancient time, the most important athletic meetings of the Greeks were parts of religious festivals: the Olympic Games that were held in the honor of Zeus, king of the Greek gods. Ironically, the end of the ancient Olympic games was a result of the religious convictions of the Roman emperor who had invaded Greece; he was a Catholic. Proofs of the inter-influence between religion and sports in history were countless. However, as to modern sports, its relationship with religion is no more the same. It is concluded that it is not so much the forms of religion but the values of it that have been carried over into modern sports. 

Sports contests always took place in the context of a religious festival in honor of a god and near a sanctuary. The origin of the contests was also explained by the intervention of gods and mythical heroes. The Olympic games lasted five days, but only on two days, there were contests. On the first day, the athletes and the hellanodikai (judges of the greeks) swore not to offend the rules in a solemn oath to Zeus. On the third day, the climax of the festival, the contests gave way to a large sacrifice to Zeus. Participation in this sacrifice was the most important task of the representatives of other cities who traveled to the sanctuary. 

Also, the success of the athletes was connected to the favor of the gods. Therefore, victors dedicated their victory crown in the temple of the city god at their homecoming. Pindar traced the descent of the celebrated athletes back to a god or hero. Some fifth-century athletes, such as Theagenes of Thasos, even received the status of demi-god or hero after their death.

Over time, the Games flourished, and Olympia became a central site for the worship of Zeus. Individuals and communities donated buildings, statues, altars and other dedications to the god. The most spectacular sight at Olympia was the gold and ivory cult statue of Zeus enthroned, which was made by the sculptor Pheidias and placed inside the temple. The statue was one of the Seven Wonders of the Ancient World, and stood over 42 feet high. A spiral staircase took visitors to an upper floor of the temple, for a better view of the statue. 

People who were not Greek could not compete in the Games, but Greek athletes traveled hundreds of miles, from colonies of the Greek city-states. These colonies were as far away as modern-day Spain, Italy, Libya, Egypt, Ukraine, and Turkey. 

A city-state, called a polis, was a typical Greek settlement, with a fortified city and a defensible citadel at the center of a territory, which might include other villages. The polis of Attica was made up of Athens and its environs, for example, and the Acropolis was its fortress. The Greek city-states began to establish colonies from the mid-8th century on.