In the Middle Ages, grammar formed an established part of a broad educational scheme, the Liberal Arts. Defined as their foundation, grammar was a gateway to literary culture, both secular and religious. Grammatical treatises taught how to use the Latin language correctly and additionally provided technical tools for interpreting literature. Medieval grammarians inherited from Antiquity a large number of textbooks, of which the works of Donatus and Priscian became authoritative. Donatus' Ars minor provided the model for teaching the basic language skills at the secondary level, while Priscian's Institutiones grammaticae established itself as the principal object of commentary at a more advanced level. All levels of teaching underwent a heavy influence of logic in the Middle Ages. The two principal genres within which medieval teachers developed their ideas on language were the ars grammatica and commentary. However, specimens of other ancient approaches to language teaching also enjoyed a continuous popularity. They include regulae ('rules', 'patterns'), and parsing grammars. Some new medieval forms of grammar writing also arose, such as verse grammars, lexicographical treatises, and quaestiones. By describing the evolution of all the subgenres of medieval grammar writing, this book aims at creating a balanced picture of grammar teaching in medieval Europe.