Born into an affluent Jewish family in Berlin in 1905, during his university years he not only trained in classical philology under some of the giants of the age, including Werner Jaeger, Eduard Norden and Ulrich von Wilamowitz, but impelled by an interest in philosophy he also attended the lectures of Ernst Cassirer on Kant, heard the phenomenologist Edmund Husserl, and studied with the existentialists Karl Jaspers and Martin Heidegger. He gave what he called "an existentialist interpretation" to the classical Neoplatonist Plotinus in his 1929 dissertation under Ernst Hoffmann at Heidelberg. In 1931, sponsored by Heidegger, he began to work on the most important Platonist of the Renaissance, Marsilio Ficino.
The Nazi victory in 1933 ended Kristeller's career in Germany. But he found support in Italy, especially from the philosopher and former Minister of Education Giovanni Gentile, who secured for him a position as lecturer in German at the Scuola Normale Superiore in Pisa, the most elite university in Italy. It was at the Scuola Normale that Kristeller completed his first great works in the Renaissance: the Supplementum Ficinianum (1937) and The Philosophy of Marsilio Ficino (1943).
The former remains to this day fundamental for the texts and information it contains and for Kristeller's masterful discussion (in Latin, of course) of the origins and history of Ficino's many writings. The latter had been written in German by 1938, but could not be published until it was translated into English five years later because Mussolini's racial laws of August 1938 terminated Kristeller's Italian career and drove him to seek a third homeland.
With the help of Gentile and others, especially the Yale University historian Roland Bainton, he sailed from Genoa in February 1939 and by March was teaching a graduate seminar at Yale on Plotinus. In the autumn of 1939 Kristeller signed a one-year contract to teach philosophy at Columbia University. Thus began a relationship with Columbia which ended only with his death 60 years later as Frederick J. E. Woodbridge Professor of Philosophy Emeritus. The next year, when he married the fellow German refugee Edith Lind Lewinnek MD, Kristeller acquired the second constant element of his life in America.
During the war years Kristeller developed his most far-reaching theories concerning the Renaissance, theories which he first published in an article in the 1944-45 issue of Byzantion, entitled "Renaissance Humanism and Scholasticism". In essence, Kristeller argued that Renaissance humanism was not a philosophy but a phase in the Western rhetorical tradition stretching back to classical antiquity and emerging in the more immediate past out of specifically Italian medieval rhetorical traditions.
The power of Kristeller's interpretation lies in the fact that he sited humanism not only culturally but also economically and socially within the Italian context. At Columbia, he also came to have a deep appreciation of Renaissance Aristotelianism. Hence, he stressed that, far from being a dying medieval residue, scholasticism in Renaissance Italy was a buoyant, growing cultural force and produced some of the most daring thinkers of the age.
He had the chance to elaborate on his ideas in the Martin Classical Lectures at Oberlin College in 1954. After these were published in 1955 as The Classics and Renaissance Thought, and then again, combined with other essays, in Renaissance Thought: the classic, scholastic, and humanist strains (1961), Kristeller reached a very wide educated audience and began to speak with almost oracular authority.
This authority stemmed in no small part from the first volumes of Kristeller's Studies in the Renaissance (1956) and Iter Italicum (1963). The first volume of Studies may be the single most important collection of articles on the Renaissance by one scholar ever published. Not only did it bring together disparate studies of Kristeller on Marsilio Ficino and Renaissance Platonism, but also fundamental articles on humanism, scholasticism, the Italian language, and music. There were eventually four volumes of Studies, the last appearing in 1996.
Iter Italicum was born in 1945 when Kristeller showed Fritz Saxl of the Warburg Institute in London the notebooks of manuscript information he had compiled during his Italian years. Saxl agreed that this material should be published and that the Warburg would sponsor the project. They decided to call the work Iter Italicum. The subtitle gives a fair description of its content: "a finding list of uncatalogued or incompletely catalogued humanistic manuscripts of the Renaissance in Italian and other libraries". But neither of them grasped then the full immensity of the project. The notebooks were only the start. It would take many more research trips to flesh them out.
The first volume did not appear until nearly 20 years after. And it would take five more volumes, each with its text in double columns and smallish print, the last appearing in 1992 and its index in 1996, before the work was done. These volumes marked Kristeller as one of the greats of historical scholarship. Iter Italicum, produced by Kristeller virtually single-handedly, is comparable in scope and detail with the corpora of inscriptions and texts compiled by teams of scholars in previous centuries.
With Iter Italicum, Kristeller did more than expose a vast fund of primary data. He also helped to change the culture of manuscript research. From the very start, in the 1930s, he sought out manuscripts in order to share his findings with the young normalisti (as students at the Scuola Normale Superiore at Pisa are called). After coming to America, he happily passed on his manuscript data to others. Decades before any particular volume of the Iter appeared, many of the manuscripts it listed had already become public knowledge as Kristeller constantly answered queries of fellow scholars and allowed scholars to consult his typescript in his home or at the Warburg.
Encouragement of the scholarship of others, in fact, constituted one of the leitmotifs of Kristeller's life. Some of the greatest Italian Renaissance scholars of the last 40 years were the normalisti who had come under Kristeller's spell during his time in Italy. Coming to America, he was one of the founders of the Renaissance Society of America, President of the Medieval Academy of America, and the chief inspirer of Catalogus Translationum et Commentariorum, the ongoing project that aims to chart the fortune of all extant classical works through the Middle Ages and Renaissance.
Kristeller's bibliography seems larger than the telephone directory of many small towns. But publications were only one of the ways he exercised influence. He had many students at Columbia and even more outside Columbia. He carried on a vast correspondence, the full extent of which will only become apparent when his papers are studied at Columbia's Rare Book Room.
Although engulfed in honours (the Serena Medal of the British Academy in 1958, the Premio Internazionale Galileo Galilei in 1968, Commendatore nell'Ordine al Merito della Repubblica Italiana in 1971, fellowship of prestigious academies of arts and sciences in Europe and America, many honorary degrees), Kristeller could never resist helping any student or a scholar who sought him out. For good reason seven different homage volumes have been dedicated to him, each spontaneously organised by disparate groups of scholars in Europe and America.
Paul Oskar Kristeller, philosopher: born Berlin 22 May 1905; Lecturer, German University and Scuola Normale Superiore, Pisa 1935-38; Lecturer in Philosophy, Yale University 1939; Associate in Philosophy, Columbia University 1939-48, Associate Professor 1948-56, Professor 1956-68, Frederick Woodbridge Professor of Philosophy 1968-73 (Emeritus); married 1940 Dr Edith Lewinnek (died 1992); died New York 7 June 1999.