Next we have the Vārttikas or "Notes" of Kātyāyana (probably third century B. C.) on 1245 of Pāṇini's rules, and, somewhat later, numerous grammatical Kārikās or comments in metrical form: all this critical work was collected by Patanjali in his Mahābhāshya or "Great Commentary," with supplementary comments of his own. He deals with 1713 rules of Pāṇini.