Dominican apologete and early Thomistic commentator; b. Ulm, Germany, c. 1476; d. Cologne, Aug. 26, 1536. Köllin (Kollin, a Colle, Kolyn), the son of an undertaker, entered the Order of Preachers in 1492, eight years after the entry of his brother Ulrich (1469–1535). He studied philosophy and theology at Ulm, then matriculated at the University of Heidelberg in 1500. After serving as biblicus (1501), bachelor of the Sentences (1503), and master of students (1505), he became a master of theology in 1507. The same year he was elected prior of the Dominican community and became dean of the theology faculty of the university. At that time he began his lectures on the Summa theologiae of St. Thomas Aquinas. At the insistence of the theology faculties of Heidelberg and Cologne, and with the permission of Cardinal T. de Vio cajetan, then master general, Köllin published his most important theological work, a commentary on the la2ae of the Summa (Cologne 1512). His other contributions to moral theology include Speculum vitae (Cologne 1518) and Quodlibeta (Cologne 1523). His influence led to the introduction of the Summa theologiae as the standard theological textbook in place of the Sentences of Peter Lombard.
Köllin was probably the most important Catholic theologian in Germany at the time of the Reformation. He energetically defended Catholic doctrine against the teaching of the Lutherans in his Eversio Lutherani Epithalamii (Cologne 1527) and Adversus caninas Martini Lutheri nuptias (Tübingen 1530). From 1528 until his death he was inquisitor for the ecclesiastical provinces of Mainz, Trier, and Cologne.
Bibliography: j. quÉtif and j. Échard, Scriptores Ordinis Praedicatorm, 5 v. (Paris 1719–23) 2.1:100. j. wilms, Der Kölner Universitätsprofessor Konrad Köllin (Cologne 1941). n. paulus, Die deutschen Dominikaner im Kampfe gegen Luther, 1518–1563 (Freiburg 1903) 111–134.