The types of drama are distinguished by the theorists according to the use which they make of the various dramatic elements enumerated. The highest of the ten main forms, Rūpakas, is the Nāṭaka or heroic comedy. The term is generic; it may denote any representation whether by pictures or dumb show, but it has also the more important specific sense of the drama proper. The subject of a Nāṭaka [731] should be drawn from tradition, not invented; the hero should be a king, royal sage, or god, who may appear in human form; the dominant sentiment must be the heroic or the erotic, but all may be illustrated, and that of wonder is well suited for the dénouement, which should be led up to through the whole series of stages of the action and junctures. The end must be happy; tragedy is forbidden, though the prohibition is unexplained. The prose should be simple without elaborate compounds; the verses clear and sweet; the Prākrits should be varied; the whole style noble and harmonious, with full use of all the beauties and the adventitious attractions of the song and the dance as well as music. The number of acts should be from five to ten; if a play contains every kind of episode, it is styled a Mahānāṭaka, if it has ten acts. The rule is generally obeyed, but late dramas styling themselves Nāṭakas are known of one (Ravidāsa’s Mithyājñānaviḍambana), two (Vedāntavāgīça’s Bhojacarita), three, or four acts, [732] and one comparatively early work exists in one version of fourteen acts, without any passage in Prākrit, the Mahānāṭaka; the Adbhutārṇava of a Kavibhūṣaṇa has twelve acts. The name of a Nāṭaka should be derived from the hero or the subject-matter, and this is regularly the case. Four or five is the number of chief personages permitted.