The side of the non-Arabs in this literary quarrel was vehemently espoused by a party who called themselves the Shu‘úbites (_al-Shu‘úbiyya_),[512] while their opponents gave them the name of Levellers (_Ahlu ’l-Taswiya_), because they contended for the equality of all Moslems without regard to distinctions of race. I must refer the reader who seeks information concerning the history of the movement to Goldziher's masterly study,[513] where the controversial methods adopted by the Shu‘úbites are set forth in ample detail. He shows how the bolder spirits among them, not satisfied with claiming an _equal_ position, argued that the Arabs were absolutely inferior to the Persians and other peoples. The question was hotly debated, and many eminent writers took part in the fray. On the Shu‘úbite side Abú ‘Ubayda, Bírúní, and Ḥamza of Iṣfahán deserve mention. Jáḥiẓ and Ibn Durayd were the most notable defenders of their own Arabian nationality, but the 'pro-Arabs' also included several men of Persian origin, such as Ibn Qutayba, Baládhurí, and Zamakhsharí. The Shu‘úbites directed their attacks principally against the racial pride of the Arabs, who were fond of boasting that they were the noblest of all mankind and spoke the purest and richest language in the world. Consequently the Persian genealogists and philologists lost no opportunity of bringing to light scandalous and discreditable circumstances connected with the history of the Arab tribes or of particular families. Arabian poetry, especially the vituperative pieces (_mathálib_), furnished abundant matter of this sort, which was adduced by the Shu‘úbites as convincing evidence that the claims of the Arabs to superior nobility were absurd. At the same time the national view as to the unique and incomparable excellence of the Arabic language received some rude criticism. [Sidenote: Assimilation of Arabs and Persians.] [Sidenote: Enthusiasm for learning in the early ‘Abbásid period.]