The ancient Stadium, or race-course, was erected in the valley, as well as a temple to Zeus, in which the victors of the games were given wreaths of wild olive. These wreaths were valued more than any other prize or distinction in Greece. Indeed at Olympia no other reward was given save the simple, wild olive branches, which were plucked from the sacred grove in the Olympian plain, and twined into a wreath. But when the victor returned to his own country, he was loaded with gifts and honours, for he had gained for his State and for his relations a glory which all longed to possess. In the Olympian temple, in later days, there was a marvellous statue of Zeus in gold and ivory, wrought by the genius of Pheidias, the greatest sculptor of Greece. The games were open to all, and spectators as well as competitors flocked to Olympia from every state in Greece. To the Greeks these games were part of their religion; they were rites pleasing, so they believed, to the gods. Should there be war between any of the Greek States at the time of the games, all hostile acts were forbidden in Olympia. Until the festival was over, those who had been in arms, one against another, might meet in safety and in peace. Twice or thrice an armed force made its way into the sacred territory of Elis to interfere with the games. This to the Greeks was sacrilege. In the earliest times the games lasted only for one day, and a simple foot-race was the only event. But soon the festival came to last for five days, for there were now, not only foot-races, but wrestling, boxing, racing in armour, and above all else chariot races. In these races it was not the driver who, if successful, won the wreath of olive, but the owner of the chariot. On the first day of the games, sacrifices were offered to the gods, on the following three days the races were held, while on the last day the people marched in procession to the temple and again offered sacrifices and feasted. At the end of every four years the games were celebrated; the time between the games being called an Olympiad. The year 776 B.C. was counted as the first Olympiad, the second began in 772 B.C. In ancient times the Greeks reckoned their dates by the Olympiads, thus an event was said to take place in a certain year of a certain Olympiad. Games were held at many other places as well as at Olympia, but the three most important celebrations, after the Olympian, were the Isthmian, the Pythian and the Nemean. To these festivals came the poets of Greece, prepared to celebrate in song the skill of the victors. During the intervals between the games, great numbers of the people assembled in a hall to listen to the poets while they recited their poems.