Various points in the biography of the Prophet and the old Muslim tradition are meant to support this idea and simultaneously to contradict the Arab concept of the inferiority of all non-Arab peoples. Arab poetry mentions Persian sword sheaths and mails, which are described with a word taken from the Persian. The contempt of the foreign nation was enhanced by the supremacy now gained by the Arab tribes over the state which had once controlled them. It is also true that old noble families, whose descendants were known in Muslim times as dihqans, countered the racial pride of the Arabs with a pride in their own ancestors which insulted Arab society. Contact with Persians and Greeks had established a culture there which far exceeded the normal level of Arab civilization and probably became the source from which select Arabs gained theirs. Arab opinion in the early days of Islam was even strict about a freeborn Arab woman marrying a foreigner.