The octagonal prism of Sennacherib BM 103000, today in the Middle East collection of the British Museum, is well-documented as a purchase made from the antiquities dealer Ibrahim Elias Gejou. However, the circumstances that brought this object to London from Iraq, as well as the trial this acquisition triggered in France have not been explored in scholarship. Yet, several documents survive and preserve this history. The letters that Ibrahim Elias Gejou sent about the prism to E.A. Wallis Budge, Keeper of Assyrian and Egyptian antiquities at the time, still exist today in the archive of the British Museum. While in France, records of the court case brought against Gejou by Benjamin Minassian who accused Gejou of having sold the prism without his knowledge, are to be found in the Archives de Paris. Read together, these documents narrate a chronology of events that begins with the appearance of the prism on the antiquities market and go much beyond a French court of law. To reconstruct this long-forgotten part of BM 103000's biography, this case study examines a dispute over the ownership of an artefact illegally removed from Iraq specifically to be sold to the British Museum, and how it impacted the parties who sold it.