Medievalist, Chairman of the Department of Medieval Art and The Cloisters, Metropolitan Museum of Art, 1968-1972. Deuchler attended a gymnasium in Zürich before studying art history at the University of Paris. He received his Ph.D. from the University in Bonn in 1956, writing his dissertation on the stain glass of Laon cathedral under Herbert von Einem. He was appointed a Privatdozent of art in 1964 at the university in Zürich. He married fellow art historian Karin Lauke, a specialist in 17th-century Bolognese art. He returned to Bonn as an assistant under von Einem. Deuchler joined the Bibliotheca Hertziana, Rome, in 1966 as an assistant. In 1968, Metropolitan Museum of Art director Thomas Hoving hired Deuchler to be chair of medieval art and curator of the Cloisters, the Met's medieval museum in Fort Tryon Park. It was the position Hoving himself had held before becoming director, though Deuchler officially replaced William Forsyth, acting curator. He was concomitantly appointed professor of medieval arts at New York University. Deuchler set about making the Cloisters a center for medieval scholarship, not simply a museum. In coordination with the centenary of the Metropolitan, he mounted the Met show "The Year 1200" in 1970 and an accompanying conference of the same title. He resigned from the Met in 1972 to become professor of art history at the University in Geneva. He was subsequently named director of the Swiss Institute, Istituto Svizzero di Roma, Rome. In 1984 he published on monograph on the trencento painter Duccio. He was appointed president of the Foundation Langmatt Sidney and Jenny Brown, which runs the Villa Brown in Baden, Switzerland, an art museum in the home of a former industrialist. He retired to Florence. In 2005 the Metropolitan acquired Duccio's "Madonna and Child" for the highest price ever paid by the museum for a painting. The work, which most scholars had attributed to the master, was not endorsed by Deuchler in his Duccio monograph. In defense of the Met's acquisition, Keith Christiansen, Old Master paintings curator at the Met, described Deuchler's scholarship as "eccentric." (Tomkins)
Die Chorfenster der Kathedrale in Laon Ein ikonographischer und stilgeschichtlicher Beitrag zur Kenntnis nordfranzösischer Glasmalerei des 13. Jahrhunderts. Bonn, 1956; Der Tausendblumenteppich in Bern: Einführung. Stuttgart: Reclam, 1966; Der Ingeborgpsalter. Berlin: de Gruyter, 1967; A Short History of Painting from Cave Art to Jackson Pollock. New York, Abrams, 1968; The Year 1200. New York: Metropolitan Museum of Art, 1970; The Cloisters Apocalypse. New York, Metropolitan Museum of Art, 1971; and Roethlisberger, Marcel, and Lüthy, Hans, and Wüthrich, Lucas. La peinture suisse: du Moyen Âge à l'aube du 20e siècle. Genva: Skira, 1975, English, Swiss Painting: from the Middle Ages to the Dawn of the Twentieth Century. New York: Rizzoli, 1976; and Wirth, Jean. Elsass: Kunstdenkmäler und Museen. Stuttgart: Reclam, 1980; edited. Museen der Schweiz. Zürich: Ex Libris, 1981; Duccio. Milan: Electa, 1984; and Zarnecki, George, and Hutter, Irmgard. Romanik, Gotik, Byzanz. Stuttgart: Belser, 1986; Ars Helvetica: die visuelle Kultur der Schweiz. Disentis: Pro Helvetia/Desertina, 1987-; and Bucher-Schmidt, Gisela. Kunstbetrieb. Disentis: Desertina Verlag, 1987; Stichjahr 1912: Künste und Musik der frühen Moderne im Urteil ihrer Protagonisten. Regensburg: Schnell & Steiner, 2003.
"Swiss is Named Cloisters Head, Young Medievalist to Take Over Museum in Fall." New York Times May 26, 1968, p. 72; Hofmann, Paul. "Little-Known Impressionist Treasure." New York Times. June 21, 1992, Section 5, p. 25; Schweizerlexikon 3 (1993): 161; Tomkins, Calvin. "The Missing Madonna." New Yorker, July 11, 2005, p. 42.