 The series incorporates a number of prominent historical figures from the field of Egyptology as characters, including Howard Carter, William Flinders Petrie, Gaston Maspero, George A. Reisner, and E. A. Wallis Budge, whom Emerson considers an arch-rival (even if the feelings are not mutual).Another recurring character is that of Cyrus Vandergelt, an American entrepreneur who finances a number of archaeological expeditions in the Valley of the Kings (with little success) and becomes a close friend and confidant of the Emerson clan.The Vandergelt character is at least partly based on Theodore Davis, the American entrepreneur who first hired Howard Carter to dig in the Valley of the Kings, and who himself appears in "The Ape Who Guards the Balance".