Headquarters of General George Washington at Valley Forge, Pennsylvania not far from White Deer Valley in 1777-1778, wherein both William Lee-Margaret Thomas would have lived, worked and possibly loved each other. Martha Washington also spent extensive periods of time there with her husband.
Lee's wife was Margaret Thomas Lee, a free African American from Philadelphia who had worked as a servant in Washington's headquarters during the war. Although slave marriages were not recognized by Virginia law, in 1784, at the couple's request, Washington tried to arrange having Margaret move to Mount Vernon to live with her husband. Whether or not she ever came to Mount Vernon is unknown.
One of the most amazing historical distortions about George Washington's triumphant wintering at Valley Forge was the deliberate and successful campaigns by ante-bellum artists and writers to eradicate images or suggestions of the sizeable Native American and African heritage soldiers and civilians in and around the encampment. Yet, Washington's own records tell a different tale from what America's teachers have been indoctrinated to teach; and, refuse to read or dismiss with ridicule any suggestions to the contrary.
Margaret Thomas was employed as a washer woman at the Valley Forge Military encampment of the Continental Army during the winter of 1777-1778. It can be safely assumed that she would have met and known William Lee during that period. It is not known whether or not she followed Washington's headquarters as it moved into Washington's spring offensive campaigns after Valley Forge.
Whatever the case may be George Washington viewed her relationship with William Lee to be that of man and wife; likely not knowing she was already married. It is almost a certainty, the marriage was not legally recognized in Virginia where marriages between slave and free was illegal; and, would certainly explain her refusal to accompany William back to his past at Mount Vernon, whether she loved him or not.
Census data from year 1850 indicates that she was living as a White woman in Adams County Pennsylvania in the household of her son born about 1801.
Person Details for Margaret Thomas in household of Conrad Thomas, "United States Census, 1850" — FamilySearch.org
United States Census, 1850
Menallen, Adams, Pennsylvania, United States
Conrad Thomas Conrad Thomas
Mary Thomas Mary Thomas
Sarah Thomas Sarah Thomas
John Thomas John Thomas
Benjamin Thomas Benjamin Thomas
Andrew Thomas Andrew Thomas
Mary Thomas Mary Thomas
Hirschfeld, Fritz. George Washington and Slavery: A Documentary Portrayal. University of Missouri Press, 1997.
Wiencek, Henry. An Imperfect God: George Washington, His Slaves, and the Creation of America. New York: Farrar, Straus and Giroux, 2003.
The 1800 U.S. Census reveals only one person named Margaret Thomas, living in the household headed by Jonathan Thomas in Upper Dublin of Montgomery County, Pennsylvania. It is not known whether or not William fathered any children with her, but research suggests a son may have been born who then became an AME minister whose wife (Kissi Lee) also became ordained and famed for her evangelism. We do not know, but have a need to understand that wars are painful for generations that suffer them. William Lee, so we believe, could not stay out of Virginia without brewing consequences for his brother Frank and other family members. So far as we know, William may have even fathered other offspring by women of his youth at Mount Vernon and surrounding plantations.