The Making of The Age of Reptiles Mural
Zallinger painting Edaphosaurus in the monochromatic stage of the mural project. Note the grid lines used to transfer the sketch to the underpainting.

In early January 1942, during my last year at the Yale School of the Fine Arts, I had the good fortune to be offered some illustration work.… Dr. Albert E. Parr, then Director of the Yale Peabody Museum of Natural History…had been unhappy with the appearance of the Great Hall of the museum,… and he therefore asked Lewis E. York, one of my professors at art school, if he would recommend an artist who could paint it. Their discussion evidently went something like this:

Parr: There is this large wall space, which would be suitable for applying some sort of decoration, probably a series of portrayals of beasts represented by skeletons in the hall — or some such thing. Lewis, do you know anyone who could undertake such a work?

York: Sure. And, you already know him. It’s Rudy. He has been doing all those seaweed drawings for you.

As of March 1, 1942, I was appointed to the staff of the Peabody Museum to devote myself exclusively to the wall-painting project.


In natural history museums, the traditional convention for painted restorations of ancient animals made use of a single animal or a group of one or perhaps a few species, which strictly observed a geological time frame and location. Dr. Parr ond others talked about painting a series of pictures showing dinosaurs with other animal and plant life that would cover the east wall of the Great Hall and would help the public envision as living animals the beasts that were represented by skeletons in the hall.

I recall pondering over that long brick wall and wondering how it could be divided into panels — separate framed panels. That format violated one of the basic tenets of mural design.… I ultimately proposed a different concept, that of using the whole available wall … for a “panorama of time,” effecting a symbolic reference to the evolutionary history of the earth’s life.…

I began my work on the actual wall in October 1943.… Vividly etched in my memory is my trepidation as I scanned that endless wall while holding a slender stick of charcoal in my hand, about to begin my work with a tool seemingly so inadequate to the task. However, I regained composure and began what turned out to be a 3 and 1/2 year project.…

This technique, called fresco secco (from the Italian fresco, plaster, and secco, dry) is not often practiced today for many reasons, among them the difficulty of painting at the site.… Moreover, there are very few painters who have acquired the competence to execute the process and equally few painters in egg tempera able to carry out the technical preparation for fresco secco. …[T]his technique provides durability second only to buon fresco, in which pigments are infused into wet plaster, and was most notably practiced by Michelangelo in the Sistine Chapel. The secco painting allows for intricacies of detail not possible in the other technique — a deciding factor in its selection.

During the 3 and 1/2 years I painted on the wall, the Great Hall was always open. Students, colleagues, and the general public thus had a rare opportunity to witness the gradual development of a large painting, created by means of a technique uncommon in the 20th century. I completed the painting on June 6, 1947. My mentor for technical information and aesthetic concerns was my long-time professor, faculty colleague, and friend Lewis Edwin York, chairman of the department of painting at the Yale School of the Fine Arts (1937–1950). His mentor in these matters was Daniel Varney Thompson, who was the primary translator of Cennino Cennini’s 15th-century tome about “the practice of the art.”… I will forever recall the day, when the painting was nearing completion, that York brought this living legend, Thompson, into the Great Hall and I was privileged to meet and talk to the man whom I had revered for so long. Professor York later told me that Thompson had stated, “That wall is the most important one since the 15th century” — debatable, of course, but, considering the source, most gratifying.

From The Great Dinosaur Mural at Yale: The Age of Reptiles, by Vincent Scully, Rudolph F. Zallinger, Leo J. Hickey, and John H. Ostrom, © 1990 Peabody Museum of Natural History, Yale University. All rights reserved