The school included architects, city planners, urban designers, painters, graphic designers, photographers, sculptors and printmakers. People and ideas commingled, as in some idealized classical agora. His faculty advisor, Christopher Tunnard, and teachers Dean Charles Moore, Robert Venturi, Paul Rudolph and James Stirling were hugely influential.

While at Yale, Rosen was a teaching fellow in the Department of History and taught the course “The History of the City.” He also was a teaching assistant in the advanced studio program of the architecture school.

Underwritten by grants from the Ford Foundation and the University of Chicago, Rosen participated in the design and restoration of the colonial city of Belo Horizonte in Brazil. His work was published in the British magazine Futures and the French design magazine Cree.

He also continues to be influenced by his experience as artist-in-residence at the excavations at Mycenae, Greece, under classical archaeologist George Mylonas. Rosen was responsible for drawing artifacts, floor plans and supervised an ongoing site at The Citadel.

Rosen started showing paintings in New York City at the Andre Emmerich Gallery, curated by Robert Miller, soon after receiv in his graduate degree from Yale in 1970.

At the same time, he owned Chiron Press, which co-published and printed limited editions of prints and multiples for artists such as Alex Katz, Kenneth Noland, Claes Oldenburg, Larry Rivers, Tom Wesselmann, Alexander Calder, Lee Krasner and Jules Olitski. Chiron Press was among the first American shops to work with artists to build and print modern images. It was noted for being innovative and experimental.

In 1979, he started Upper South Studio, a combination of his painting career and the utility of Chiron Press.