This book deals with a text which has been a mystery to research concerning its temporal and spatial sphere up to now. Nevertheless it is of great importance to understand late ancient linguistics and their continuing influence on the Middle Ages. This comment to Ars maior by Donat being in the tradition of Servius has been known to be written by the Christian statesman and author Cassiodor. Nonetheless the authorship is still not solved because assigning the text to Cassiodor is less based on transmission, but rather on the rash theory of a French philologist who edited the text for the first time in the 17th century. With regard to content the tract is about the octo partes orationis, namely the eight parts of speech noun, pronoun, adverb, participle, conjunction, preposition and interjection. For today's user this text has been difficult to get hold of because just a part of the existing transmission was the basis for the first and only edition of 1679 and its reprint of 1848. Therefore a revised edition is placed at the beginning of this thesis which considers apart from the old version a still existing manuscript from early Carolingian times as well as a broad secondary transmission. The second part consists of a comment regarding an analysis of language and content. Its aim is to answer the questions concerning time and place of origin, its position in literary history, its author and its continuing influence. Consequently this specific version enriches the series of comments written by Donat transmitted from late ancient times. Additionally it contributes to modern linguistics regarding the research of early stages in language theory.