Emily Appleton Gates is the ex-wife of Patrick Henry Gates, whom she divorced, in her words, because one of them had to grow up and stay home to take care of Ben. (It should be noted, however, that that statement was uttered under duress, as Wilkinson had threatened to shoot Patrick if she didn't cooperate with his plan.) She is the mother of Benjamin Franklin Gates. It's clear that Emily is of British descent, but the audience is never told how she and Patrick met, when, or under what circumstances other than her statement that she didn't really fall in love with him--that it was "...that was just excitement, adrenaline, and tequila...and I was just trying to get course credit..." Other such subtle clues are given throughout the film as to their history together, but nothing is ever stated for certain. For example, at Mount Rushmore, Patrick exclaims, "...I'm so sorry for getting you into this mess!" and Emily replies by saying that the last time he said that to her, it was the night before their wedding.
Dr. Appleton studies Ancient Native American languages and is the chairperson of the Linguistics department for the University of Maryland. Mitchell Wilkinson forces her to go to Mount Rushmore to force Ben to cooperate, and so that the Cíbola can be found with her assistance.