A new CT scan investigation suggests that the mummy known as the Elder Lady is not Nefertiti—chief wife of the powerful pharaoh Akhenaten—as many archaeologists had speculated.

Instead, the research team suggests, the mummy may be Queen Tiye, his mother. A corpse found nearby, the Younger Lady, could be Kiya, Akhenaten's second wife and the woman many experts believe is the mother of King Tut.

Akhenaten, of Egypt's 18th dynasty, reigned around 1350 B.C. and is famed for making one of the first known attempts at monotheism, worshipping the previously obscure sun god Aten. Declaring Aten Egypt's one true god, Akhenaten closed temples honoring other deities and forbade their worship, while erecting massive new temple complexes and founding a new capital city, Akhetaten (now Amarna), to honor Aten.

But the radical new religion quickly fell out of favor after Akhenaten's death. The new temples were razed, and eventually the entire line of Amarna pharaohs—including Tut, who ruled for nine years later in the century—were excised from the historical record, presumably part of attempt to destroy any reference to the cult religion.

A one-hour National Geographic Channel special on the discoveries—Nefertiti and the Lost Dynasty—will air Monday, July 16, at 9 p.m.

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