The date of Vātsyāyana thus becomes of interest, but unluckily it is still undefined with any precision. [710] It certainly seems, however, that Kālidāsa was familiar with a text very similar to and perhaps identical with the Kāmaçāstra, and this reasonably may be regarded as giving A.D. 400 as the lower limit of date. That the Kauṭilīya Arthaçāstra has been used by Vātsyāyana gives no precise result, in view of the difficulty of dating exactly that text. But the mention by Vātsyāyana of the Ābhīras [711] and Andhras certainly suggests, taken into conjunction with his silence as to the Guptas, that he wrote before the power of the latter had established itself in western India, and we may assign his work to approximately A.D. 300. If so we must believe that already in Kālidāsa’s age the Prākrits of his characters were more or less artificial, and with this well accords his introduction of Māhārāṣṭrī for the verses of those to whom Çaurasenī is assigned in prose, an obviously literary device. Elaborate rules for the use of language [712] by the characters are given in the Nāṭyaçāstra and, in much less detail, by the Daçarūpa. The use of Sanskrit is proper in the case of kings, Brahmins, generals, ministers, and learned persons generally; the chief queen is assigned it, and so also ministers’ daughters, but this rule is not in practice observed. On the other hand, it is used by Buddhist nuns, hetaerae, artistes, and others on occasion. It is a rule that in the description of battles, peace negotiations, and omens Sanskrit shall be resorted to, and this is done by Bṛhannalā in Bhāsa’s Pañcarātra. The use of Sanskrit by allegorical female types is also found both early and late.