Of numerous relationships between male slaveholders, overseers, or master's sons and women slaves, the most notable is likely that of President Thomas Jefferson with his slave Sally Hemings. As noted in the 2012 collaborative Smithsonian-Monticello exhibit, Slavery at Monticello: The Paradox of Liberty, Jefferson, then a widower, took Hemings as his concubine for nearly 40 years. They had six children of record; four Hemings children survived into adulthood, and he freed them all, among the very few slaves he freed. Two were allowed to "escape" to the North in 1822, and two were granted freedom by his will upon his death in 1826. Seven-eighths white by ancestry, all four of his Hemings children moved to northern states as adults; three of the four entered the white community, and all their descendants identified as white. Of the descendants of Madison Hemings, who continued to identify as black, some in future generations eventually identified as white and "married out", while others continued to identify as African American. It was socially advantageous for the Hemings children to identify as white, in keeping with their appearance and the majority proportion of their ancestry. Although born into slavery, the Hemings children were legally white under Virginia law of the time.
How long were Washington and Hemings in a relationship for?