1956 , he studied philosophy and sociology under the critical theorists Max Horkheimer and Theodor Adorno at the Johann Wolfgang Goethe University Frankfurt am Main Institute for Social Research, but because of a rift between the two over his dissertation—Horkheimer had made unacceptable demands for revision—as well as his own belief that the Frankfurt School had become paralyzed with political skepticism and disdain for modern culture[6]—he finished his habilitation in political science at the University of Marburg under the Marxist Wolfgang Abendroth. His habilitation work was entitled Strukturwandel der Öffentlichkeit; Untersuchungen zu einer Kategorie der Bürgerlichen Gesellschaft (published in English translation in 1989 as The Structural Transformation of the Public Sphere: an Inquiry into a Category of Bourgeois Society). It is a detailed social history of the development of the bourgeois public sphere from its origins in the 18th century salons up to its transformation through the influence of capital-driven mass media. In 1961 he became a privatdozent in Marburg, and—in a move that was highly unusual for the German academic scene of that time—he was offered the position of "extraordinary professor" (professor without chair) of philosophy at the University of Heidelberg (at the instigation of Hans-Georg Gadamer and Karl Löwith) in 1962, which he accepted. In this same year he gained his first serious public attention, in Germany, with the publication of his habilitation. In 1964, strongly supported by Adorno, Habermas returned to Frankfurt to take over Horkheimer's chair in philosophy and sociology. The philosopher Albrecht Wellmer was his assistant in Frankfurt from 1966 to 1970.