While this work of colonization was going forward, the parent states of Greece were torn with internal dissensions, and were perpetually harassing each other in wars, of which the objects and incidents are now equally uncertain. Almost all that is known of the history of the two centuries immediately following the death of Codrus is, that they were characterized by great turbulence and confusion, and that, during their lapse, many of the Grecian states and colonies followed the example of Athens by abolishing monarchy. Others did not, till a later period, become republican, and Sparta long retained the singular form of regal government established there at the accession of the twin brothers Eurysthenes and Procles, the descendants of whom continued for several centuries to reign jointly in Lacedæmon, though, practically speaking, no state of Greece was more thoroughly republican in many important respects. Greece had been all along divided into a number of independent states, and after the abolition of kingly government, several of these were split up into as many distinct republics as the state contained of towns. These divisions of the country, and the obstacles which the almost incessant wars interposed to a free communication between the inhabitants of the different districts, necessarily prevented the advancement of the Greeks in knowledge and civilization; but fortunately, a king of Elis, named Iphitus, at length devised an institution by which the people of all the Grecian states were enabled, notwithstanding their quarrels and wars with one another, to meet periodically on friendly terms, and communicate to each other such information as might be useful for the improvement and welfare of the whole. This institution was the Olympic Festival. From a very remote period, the Greeks had been accustomed to engage in contests of strength and agility during their times of festivity, and also at the funerals of distinguished personages. Iphitus conceived the idea of establishing a periodical festival in his own dominions for the celebration of these ancient games, and of religious rites in honor of Jupiter and Hercules; and having obtained the authority of the Delphian oracle for carrying his design into execution, he instituted the festival, and appointed that it should be repeated every fourth year at Olympia, a town of Elis. To this festival he invited all the people of Greece; and that none might be prevented from attending it by the wars in which any of the states might be engaged, the Delphic oracle commanded that a general armistice should take place for some time before and after each celebration. The date of the establishment of the Olympic games (884 B. C.) was afterwards assumed by the Greeks as the epoch from which they reckoned the progress of time; the four years intervening between each recurrence of the festival being styled an _Olympiad_.