The scads of advertisements from Ancestry.com or PBS’ “Finding Your Roots” make it easy to imagine geneaology as the arena of the hobbyist or amateur historian. Sites and shows like those and others suggest that, in our highly individualistic world, ancestry is just a pastime. But in fact ancestry still has (literally) grave consequences. Matters of inheritance and heritage are at the core of many functions of the state, from birthright citizenship to Native American ancestry to matters of probate. Such is the reality now, and so it was in the founding years of the United States.

For a man of his times like George Washington, but also for men and women without his wealth or prominence, lineage was foundational. By the time he was 18, George Washington was a competent genealogist -- and he had to be. In Washington’s Virginia, family was a crucial determinant of social and economic status, and freedom.

How did Washington understand his family, and what can that tell us about the world in which he lived and played such a significant role? Thanks to a document long ignored by biographers and historians alike, we now know how fully he grasped the basic truth that genealogy is power.

Inscribed by Washington in distinct sections during the late 1740s and the early 1750s, decades before the American Revolution, the two sides of this document, held at the Library of Congress, help us to see how Washington viewed the importance of his family connections, including as a route to inheritance, and also how these relationships were crucially connected to the lives of enslaved people.