Elizabeth Martin was the heroine in the first National Treasure children's book called Changing Tides.
She was the second of four children between John Martin and his wife. She has an older brother, Harold Martin, and two younger sisters. She is friend of Matachanna, Pocahontas' half sister.
She was very outgoing. In the book, she was first introduce when Samuel Gates, one of the first two Gates to come to America, came to work as assistant record keeper to her father. The two quickly became friends, then together they work and found the treasure, and eventually fall in love.
In Midnight Ride, she and Samuel married. So by marriage, she became daughter-in-law of Benjamin Patrick Gates and Alice, sister-in-law of William Gates and Mary Wallis, and direct ancestor of Benjamin Franklin Gates.