Direct ancestors of King Charles III and the royal family bought and exploited enslaved people on tobacco plantations in Virginia, according to new research shared with the Guardian.

A document discovered in archives reveals that a direct ancestor of the king was involved in buying at least 200 enslaved people from the Royal African Company (RAC) in 1686.

The document instructs a ship’s captain to deliver the enslaved Africans to Edward Porteus, a tobacco plantation owner in Virginia, and two other men. Porteus’s son, Robert, inherited his father’s estate before moving his family to England, in 1720. Later a direct descendant, Frances Smith, married the aristocrat Claude Bowes-Lyon. Their granddaughter was Elizabeth Bowes-Lyon, the late queen mother.

The documents establishing these royal roots were found by the researcher Desirée Baptiste, while investigating links between the Church of England and enslavers in Virginia, for a play she has written.

The revelation follows the Guardian’s publication of a document earlier this month that linked the slave trader Edward Colston to the British monarchy. The latest discovery, which Baptiste made deep in the RAC archives, reveals a direct line up the Windsor family tree to the trafficking of enslaved Africans.