Zahi Hawass -- secretary-general of Egypt's Supreme Council of Antiquities -- became incensed Thursday when he learned that John Rowe, chairman of the electric utility company Exelon, kept a 2,600-year-old Egyptian coffin in his office, the Chicago Tribune reported.
Hawass was attending a press preview of the Field Museum's new exhibit, "Tutankhamun and the Golden Age of the Pharaohs," when he used the opportunity to demand that Rowe surrender the artifact or be banned from sponsorship of the exhibit.
"This doesn't belong to a person," Hawass said. "It belongs to the whole world."
He wrote letters to the Field Museum, National Geographic Society and two exhibition contractors, threatening to end his relationships with them.
Hawass hinted he may have future tiffs with Rowe, who is known to collect ancient art objects.