Oswald Mathias (O.M.) Ungers, an inspirational, dynamic educator and influential architect who brought international recognition to Cornell's Department of Architecture in the 1970s, died Sept. 30 in Germany at the age of 81 as the result of a lung infection.

Ungers had prolific professional and academic careers in Cologne and Berlin in the 1950s and '60s and came to Cornell as a visiting critic in 1965 and 1967. He was appointed to chair the Department of Architecture in 1969, serving until 1975. Known to many of his colleagues and students as Mathias or "OMU," he solidified the department's reputation as a center of architectural thought, particularly rationalism and postmodernism, and established a new graduate program in architectural design. He also utilized Cornell's academic setting to reformulate and transform his own work and thinking, which would later be realized upon his return to Germany.

Ungers is widely regarded as the most theoretically influential postwar architect in Germany. His best-known built works include the Wallraf Richartz Museum in Cologne, the Kunsthalle in Hamburg, the German Museum of Architecture in Frankfurt, libraries in Karlsruhe and Cologne, the Family Court in Berlin and the Frankfurt Exposition buildings. He also designed the residence of the German ambassador in Washington, D.C., built in 1994.

He was internationally known in academic circles for his theoretical projects and work, both in the 1960s in Berlin and the 1970s at Cornell, much of which was exhibited at the New National Gallery in Berlin in the 2006 exhibition "Cosmos of Architecture." His academic contributions have been the subject of several recent symposia, including a spring 2007 event at Cornell, and many of his writings have recently been republished in the magazine ArchPlus. Among his many honors and awards, Ungers received Medals of Honor from the Republic of Germany in 1997 and the State of Nordrhen-Westfalen in 2006.

He is survived by his wife, Liselotte, and two daughters, Sybille '82, BFA '83, and Sophia '84.