Thus there is, in the present state of our knowledge, good reason to suppose that Kalidasa lived not in the sixth, but in the beginning of the fifth century A.D. The question of his age, however, is not likely to be definitely solved till the language, the style, and the poetical technique of each of his works have been minutely investigated, in comparison with datable epigraphic documents, as well as with the rules given by the oldest Sanskrit treatises on poetics. As the popular epic poetry of the Mahabharata was the chief source of the Puranas, so the Ramayana, the earliest artificial epic, was succeeded, though after a long interval of time, by a number of Kavyas ranging from the fifth to the twelfth century. While in the old epic poetry form is subordinated to matter, it is of primary importance in the Kavyas, the matter becoming more and more merely a means for the display of tricks of style. The later the author of a Kavya is, the more he seeks to win the admiration of his audience by the cleverness of his conceits and the ingenuity of his diction, appealing always to the head rather than the heart. Even the very best of the Kavyas were composed in more strict conformity, with fixed rules than the poetry of any other country. For not only is the language dominated by the grammatical rules of Panini, but the style is regulated by the elaborate laws about various forms of alliteration and figures of speech laid down in the treatises on poetics. The two most important Kavyas are Kalidasa's Raghuvamça and Kumara-sambhava, both distinguished by independence of treatment as well as considerable poetical beauty. They have several stanzas in common, many others which offer but slight variations, and a large number of passages which, though differing in expression, are strikingly analogous in thought. In both poems, too, the same metre is employed to describe the same situation. In both poems each canto is, as a rule, composed in one metre, but changes with the beginning of the new canto. The prevailing metres are the classical form of the anushtubh and the upajati, a development of the Vedic trishtubh. The Raghuvamça, or "Race of Raghu," which consists of nineteen cantos, describes the life of Rama together with an account of his forefathers and successors. The first nine cantos deal with his nearest four ancestors, beginning with Dilipa and his son Raghu. The story of Rama occupies the next six (x.-xv.), and agrees pretty closely with that in the Ramayana of Valmiki, whom Kalidasa here (xv. 41) speaks of as "the first poet." The following two cantos are concerned with the three nearest descendants of Rama, while the last two run through the remainder of twenty-four kings who reigned in Ayodhya as his descendants, ending rather abruptly with the death of the voluptuous King Agnivarna. The names of these successors of Rama agree closely with those in the list given in the Vishnu-purana.