Peter Lombard (c.1095–1160), Italian theologian and author of the Book of Sentences (Liber sententiarum), a renowned theological sourcebook in the later Middle Ages. Peter was educated at Bologna, Reims, and Paris before teaching in the school of Notre Dame in Paris. He became a canon at Notre Dame in 1144–45 and was elected bishop of Paris in 1159. His extant works include commentaries on the Psalms (written in the mid-1130s) and on the epistles of Paul (c.1139–41); a collection of sermons; and his one-volume summary of Christian doctrine, the Sentences (completed by 1158).
The Sentences consists of four books: Book I, On the Trinity; Book II, On the Creation of Things; Book III, On the Incarnation; and Book IV, On the Doctrine of Signs (or Sacraments). His discussion is organized around particular questions or issues e.g., ‘On Knowledge, Foreknowledge, and Providence’ (Book I), ‘Is God the Cause of Evil and Sin?’ (Book II). For a given issue Peter typically presents a brief summary, accompanied by short quotations, of main positions found in Scripture and in the writings of the church fathers and doctors, followed by his own determination or adjudication of the matter. Himself a theological conservative, Peter seems to have intended this sort of compilation of scriptural and ancient doctrinal teaching as a counter to the popularity, fueled by the recent recovery of important parts of Aristotle’s logic, of the application of dialectic to theological matters. The Sentences enjoyed wide circulation and admiration from the beginning, and within a century of its composition it became a standard text in the theology curriculum. From the midthirteenth through the mid-fourteenth century every student of theology was required, as the last stage in obtaining the highest academic degree, to lecture and comment on Peter’s text. Later medieval thinkers often referred to Peter as ‘the Master’ (magister), thereby testifying to the Sentences’ preeminence in theological training. In lectures and commentaries, the greatest minds of this period used Peter’s text as a framework in which to develop their own original positions and debate with their contemporaries. As a result the Sentences-commentary tradition is an extraordinarily rich repository of later medieval philosophical and theological thought. S.Ma.