But if the Arab spirit modified the spirit of Persia in many ways, the converse action was no less strong, possibly stronger. Many political institutions, the forms of polite society, nay, of town life as a whole, luxury, art, and even the fashion of dress, came to the Arabs from Persia. In the Omayyad period Arabic poetry remains in essentials true to the methods of the old heathen Bedouin poets; though side by side with them--and more particularly in the works of the best poets--we mark the gradual growth of a more elegant style, suited to the more cultivated tastes of the towns, and even of a courtly school of poetry. Even in later times, however, the methods of the elder poets found many imitators. But after the Abbasid period the writers of Arabic poems, taken as a whole, were no longer men of pure Arab descent; many were freedmen or of humble origin and Persian or Aramaic nationality. Thus during the Moslem period even the native poets of Persia began by writing in Arabic, and hence the rising school of Persian poetry adhered closely to the traditions of the Arabic school, both in metre and all points of structure, and in subject-matter and verbal expression. Unhappily it showed itself equally ready to imitate the artificiality into which Arabic poetry had sunk at that period. It is true, indeed, that from the outset Persian poetry displayed certain distinctive features, and that its noblest achievement, the national epic, is, broadly speaking, original, though even there Arabic influence is potent in the details.