More Detail about William Costin

Back in 2016 I wrote about William Costin, then believed to be the son of John Parke Custis, Martha Washington’s son, and Ann Dandridge, her half-sister.

A couple of years ago Mount Vernon created an entry in its Digital Encyclopedia of George Washington on “The Ancestry of William Costin,” which I came across last week.

That in turn led me to David O. Stewart’s Journal of the American Revolution article “The Mount Vernon Slave Who Made Good: The Mystery of William Costin” from 2020.

The Mount Vernon page still identifies John Parke Custis as most likely to be William Costin’s father, based on a range of contemporaneous behavior and later statements.

The Custis family said nothing about that publicly at the time, of course, but they not only freed Costin and his relatives, they kept ties with them. Costin himself followed that family’s custom in giving his own children the middle name Parke.

The newer articles point out that there are no contemporaneous sources on a woman named Ann Dandridge, particularly from Mount Vernon, where the surviving records are unusually full. The earliest mentions of William Costin’s mother appear around the turn of the century when she was known as Nancy or Ann Holmes, formerly Costin.

It’s impossible to reconcile two statements about “Ann Dandridge” published in 1871—that she was a daughter of John Dandridge, Martha Washington’s father, and that she grew up as Martha’s playmate. Nancy/Ann (Costin) Holmes had children as late as 1801. It’s therefore just possible that her father was John Dandridge, who died in 1756. But she couldn’t have been about the same age as Martha Washington, born in 1731.

The Mount Vernon article posits that this Nancy/Ann had children by three men:

• William by John Parke Custis in or around 1780. Custis died in 1781.
• Four children between 1788 and 1795 by a man named Costin, possibly an overseer documented as working on a Custis plantation on Smith’s Island. William took this stepfather’s surname.
• Two children by Joseph Holmes in 1799 and 1801.

Eventually Nancy/Ann Holmes and all her children became the property of Eliza Parke Custis Law, and her husband Thomas Law manumitted the extended family in the early 1800s.