Sanskrit literature have contributed immensely to the field of historical study, it is Pāṇini who in his Aṣṭādhyāyī, first set a linguistic model with historical datas for the description of language in 5th Century B.C. Kāśikā-Vṛtti of Jayāditya and Vāmana is a well-coded gloss on Pāṇini’s Aṣṭādhyāyī. The present study discusses some historical evidences found in Kāśikā in the form of examples and counter examples which are supplied by its authors to illustrate the working of the aphorisms of Aṣṭādhyāyī. Throughout the world, the scholars have shown great interest in the field of language-analysis and in this respect Sanskrit grammatical literature have contributed immensely by studying language-behavior of Ancient India. Like any other ancient language of any part of the globe, Sanskrit has been the successful means of carrying reflections of the ancient Indian cultural heritage. Sanskrit grammarians too have not lagged behind in this mission. As objective recorders of facts, Indian grammarians have tried to reveal various aspects for the study of ancient Indian history. Knowledge of Panini’s grammar is essential for Sanskrit language. The name of Aṣṭādhyāyī comes before us by saying the grammar of Panini. Aṣṭādhyāyī is a composition of aphorisms. It is difficult to explain the meaning of aphorisms without the help of commentary text. The enormous commentaries are available on this. They deal with different perspectives of research and study. Kāśikā or Kāśikā-Vṛtti is a ‘gloss’ whose purpose is to precisely explain sūtras(aphorisms) without leaving any doubt in the minds of the readers. To illustrate the working of aphorisms of Pāṇini’s Aṣṭādhyāyī, the author of Kāśikā supply historical data in the form of examples and counter examples. Examples of Sanskrit grammatical text constitute a livelily norms of language-use which may be considered as one of its primary aspects. The description of this aspect of language-use in society in relation to various facts of social life tends to be interesting and the legitimate goal of historical investigation. It is taken for granted that the trimuni vyākaraṇa samples and records facts of ancient India from the source of natural speech. Coming unto the time of Jayāditya and Vāmana, the natural speech might be progressing rapidly towards a theoretical possibility. Still the historical recording mainly of diachronic nature noticed in the Kāśikā Vṛtti (KV) makes it appropriate a text of historical investigation. It will not be out of place to prepare below a brief but relevant outline of the nature and necessity of historical investigation when Pāṇini is claimed to be a scholar of the science of ancient Indian history having the critical attitude of accurate recording of facts in his Aṣṭādhyāyī.