During the mid-nineteenth century, along with excavators and historians, missionaries were invested in the rediscovery of Nimrud (in present-day Iraq) because its existence provided support for the validity of Biblical history: Nimrud—ancient Kalhu—was thought to be Calah, a city mentioned in the book of Genesis built immediately following Noah’s flood. One of these missionaries happened to be Dr. Henri Bryon Haskell (1830–64), an 1855 graduate of the Medical School of Maine at Bowdoin College. Dr. Haskell was able to acquire five Northwest Palace reliefs from archaeologist and world traveler Austen Henry Layard that were shipped to the United States for a total cost of $728.17.

On their arrival at Bowdoin in 1860, the five Assyrian reliefs were installed in the entrance to the Chapel. A sixth relief fragment depicting the head of the Assyrian King Ashurnasirpal II was given to the Museum by Edward Perry Warren in 1906. The original plan for the Walker Art Building did not incorporate the reliefs, and they were installed in the basement of the museum building until well into the twentieth century. They were later installed in the rotunda by Philip Beam (1910–2005) shortly after he assumed directorship of the museum in 1939. In 2007, when the Museum reopened to the public after a major renovation, the reliefs were given a prominent new location in the Assyrian Gallery, facing Park Row and the Brunswick Maine Street through a new glass exterior wall.