Abu Ali Muhammad bin-al Mustanir bin Ahmad, generally known by the name of Kutrub, was also a grammarian and philologist, and wrote books and treatises on these subjects, as also on natural history. He died A.D. 821. Philology and Arabic poetry were the special objects of the studies of Abu Amr Ishak bin Mirar as Shaibani, and in these two branches of knowledge his authority is of the highest order. He composed a number of works and treatises, and wrote with his own hand upwards of eighty volumes. He died A.D. 825. But the two earliest, and perhaps the two most celebrated, philologists were Al-Asmai and Abu Obaida, who outshone their successors for all time to come, and were distinguished--the former by his wit, and the latter by his scholarship. Abu Said Abd-al Malik bin Kuraib al-Asmai was born A.D. 739 or 740, and died A.D. 831. He was a complete master of the Arabic language, an able grammarian, and the most eminent of all those who transmitted orally historical narrations, anecdotes, stories, and rare expressions of the language. When the poet Abu Nuwas was informed that Asmai and Abu Obaida had been introduced at Harun's court, he said that the latter would narrate ancient and modern history, but that the former would charm with his melodies. Ibn Shabba was informed by Asmai himself 'that he knew by heart sixteen thousand pieces of verse composed in the measure called Rajaz, or free metre,' and Ishak al Mausili asserted 'that he never heard al-Asmai profess to know a branch of science without discovering that none knew it better than he.' No one ever explained better than Al-Asmai the idioms of the desert Arabs. Most of his works, which amount to thirty-six, treat of the language and its grammar; but he also wrote a book on the horse and different treatises on various other animals, such as the camel, the sheep, wild beasts, etc., and their physiology. Al-Asmai's contemporary, Abu Obaida, was an able grammarian and an accomplished scholar. He was born A.D. 728, and died at Busra A.D. 824, leaving nearly two hundred treatises, of which the names of many have been given by Ibn Khallikan, and most of them are of a purely philological character. There are many anecdotes about him, and many sayings of clever men regarding him. Abu Nuwas took lessons from Abu Obaida, praised him highly, and decried Al-Asmai, whom he detested. When asked what he thought of Al-Asmai, he replied, 'A nightingale in a cage,' meaning probably that a nightingale in a cage is pleasing to hear, but there is nothing else good about it. Abu Obaida he described as 'a bundle of science packed up in a skin.'