Complex sentence: She served as president of the Organization of American Historians in 1980-81 and in 1980 was appointed Robinson Edwards Professor of History at the University of Wisconsin-Madison, where she taught until retiring in 1991.
Split into simpler sentences: She served as president of the Organization of American Historians in 1980-81. In 1980 she was appointed Robinson Edwards Professor of History at the University of Wisconsin-Madison, where she taught until retiring in 1991.