Oriental Institute’s important stewards of the past protect, preserve
A 300-pound fragment of a human-headed winged bull from the Neo-Assyrian city of Khorsabad sits on a table in the Oriental Institute’s conservation laboratory. The fragment, made of gypsum, is about to get the most attention it’s had since a team of archaeologists excavated it more than 70 years ago in northern Iraq.
Alison Whyte, Assistant Conservator, guides a small vacuum nozzle over the fragment’s surface—past its carved rosette decorations and over tiny bits of dirt, some of which are more than 2,000 years old. She uses a small artist’s brush with especially fine bristles to sweep up the dust.
The preservation of cultural heritage is part of the Oriental Institute’s core mission, says Gil Stein, Director of the Oriental Institute. “All of our studies of ancient civilizations rely ultimately on physical remains—the monuments, artifacts, skeletons, and texts that have survived for millennia to be re-discovered by archaeologists. But those remains are extremely fragile,” he notes.
The conservators at the Oriental Institute ensure that future generations of scholars and museum visitors will have opportunities to study and appreciate these ancient remnants. “In a very real sense, the conservators are the most important stewards of the past,” Stein says.
Scientific and the Humanistic Linked
Whyte’s careful examination of the fragment reveals information about its place of origin. “Over here you can see soil left behind from the excavation. Its red-brown color may indicate that it was iron-rich,” she says, pointing to a tiny deposit near what appears to be an eye on the four-by-two-foot object. “We will analyze the soil residues to add to the information that we have on the artifact,” says Whyte.
After dry-cleaning the piece, Whyte will wash it with tap water before bathing it in de-ionized water.
“These are precious objects because they are so old and irreplaceable. We have to be very careful in handling them, but at the same time we can’t be so worried about handling them that we can’t do our job,” says Laura D’Alessandro, Head of the Conservation Laboratory.
The work of archaeological conservators links the sciences and the humanities. Conservators draw on the most advanced understandings of organic and physical chemistry to preserve the basic data for humanistic and anthropological studies of how ancient civilizations rose, functioned, and fell, Stein explains.
D’Alessandro adds, “Much of what we do requires an understanding of scientific processes. That’s one of the things we like about the work we do. It crosses so many disciplines, including science, art, and archaeology.”
She and her team also work with other researchers on campus and around the world to develop new techniques using CT scanning and infrared light, for example, to detect corrosion and decay.
Training Others in Techniques
Besides preserving Oriental Institute collections, the conservators also train their counterparts from the Middle East. A group of six Iraqi conservators spent six weeks this summer in a joint program between the University and the Field Museum, two of them in the Oriental Institute lab.
The Iraqis are challenged to preserve a large number of newly excavated materials, says D’Alessandro, as well as objects in the collection of the National Museum in Baghdad. Many of these artifacts were subject to the widespread looting of both the museum and archaeological sites, and they only recently have been returned to the museum.
All of the methods conservators apply reveal new information—clues that will aid scholars in assembling a more complete picture of the people who created the items. The gypsum fragment from Khorsabad is one example. Further examination of the piece will help researchers construct a story about the Neo-Assyrian culture that built the city of Khorsabad between 721 and 705 B.C.
“Our project of cleaning, cataloguing, and photographing these fragments is documenting the extensive use of paint on the figures and landscapes as well as the carved inscriptions on reliefs,” notes Geoff Emberling, Director of the Oriental Institute Museum.
The human-headed winged bull fragment will eventually be added to a web-based catalogue of the Khorsabad collection, which includes reliefs found at the palace site.
“The French excavators of Khorsabad made drawings of these reliefs,” says Emberling, “but they didn’t record everything of interest.”
By William Harms
