The natural causes which tended to unite the Greeks as a people were a common descent, a common language, and a common religion. Greek genius led the nation to trace its origin, where historical memory failed, to fabulous persons sprung from the earth or the gods; and under the legends of primitive and heroic ancestors lie the actual migrations and conquests of rude bands sprung from related or allied tribes. These poetical tales, accepted throughout Hellas as historical, convinced the people of a common origin. Thus the Greeks had a common share in the renown of their ancient heroes, upon whose achievements or lineage the claims of families to hereditary authority, and of states to the leadership of confederacies, were grounded. The pride or the ambition of political rivals led to the gradual embellishment of these traditions, and ended in ancestral worship. Thus Attica had a temple to Theseus, the Ionian hero; the shrine of Æsculapius at Epidau'rus was famous throughout the classic world; and the exploits of Hercules were commemorated by the Dorians at the tomb of a Ne'mean king. When the bard and the playwright clothed these tales in verse, all Greece hearkened; and when the painter or the sculptor took these subjects for his skill, all Greece applauded. Thus was strengthened the national sense of fraternal blood. The possession of a common speech is so great a means of union, that the Romans imposed the Latin tongue on all public business and official records, even where Greek was the more familiar language; and the Mediæval Church displayed her unity by the use of Latin in every bishopric on all occasions of public worship. A language not only makes the literature embodied in it the heritage of all who speak it, but it diffuses among them the subtle genius which has shaped its growth. The lofty regard in which the Greeks held their own musical and flexible language is illustrated by an anecdote of Themis'tocles, who put to death the interpreter of a Persian embassy to Athens because he dared "to use the Greek tongue to utter the demands of the barbarian king." From Col'chis to Spain some Grecian dialect attested the extent and the unity of the Hellenic race.