This gift of the desert--otherwise so sparing of its favors--has not failed to leave its impression upon the whole Arabic literature. Though it has produced some prose writers of value, writing, as an art to charm and to please, has always sought the measured cadence of poetry or the unmeasured symmetry of rhymed prose. Its first lispings are in the "trembling" (rájaz) metre,--iambics, rhyming in the same syllable throughout; impromptu verses, in which the poet expressed the feelings of the moment: a measure which, the Arabs say, matches the trembling trot of the she-camel. It is simple in its character; coming so near to rhymed prose that Khalíl (born 718), the great grammarian, would not willingly admit that such lines could really be called poetry. Some of these verses go back to the fourth and fifth centuries of our era. But a growing sense of the poet's art was incompatible with so simple a measure; and a hundred years before the appearance of the Prophet, many of the canonical sixteen metres were already in vogue. Even the later complete poems bear the stamp of their origin, in the loose connection with which the different parts stand to each other. The "Kasídah" (poem) is built upon the principle that each verse must be complete in itself,--there being no stanzas,--and separable from the context; which has made interpolations and omissions in the older poems a matter of ease. The classical period of Arabic poetry, which reaches from the beginning of the sixth century to the beginning of the eighth, is dominated by this form of the Kasídah. Tradition refers its origin to one al-Muhalhel ibn Rabí'a of the tribe of Taghlib, about one hundred and fifty years before Muhammad; though, as is usual, this honor is not uncontested. The Kasídah is composed of distichs, the first two of which only are to rhyme; though every line must end in the same syllable. It must have at least seven or ten verses, and may reach up to one hundred or over. In nearly every case it deals with a tribe or a single person,--the poet himself or a friend,--and may be either a panegyric, a satire, an elegy, or a eulogy. That which it is the aim of the poet to bring out comes last; the greater part of the poem being of the nature of a _captatio benevolentia_. Here he can show his full power of expression. He usually commences with the description of a deserted camping-ground, where he sees the traces of his beloved. He then adds the erotic part, and describes at length his deeds of valor in the chase or in war; in order, then, to lead over to the real object he has in view. Because of this disposition of the material, which is used by the greater poets of this time, the general form of the Kasídah became in a measure stereotyped. No poem was considered perfect unless molded in this form.