European Molly Welsh purchased Benjamin Banneker’s grandfather Banna Ka when he arrived from Senegambia in 1692. In a very unusual move, Molly freed Banna Ka and married him. Their first child, Mary, married formerly enslaved Robert, who, in another unusual move, took her last name. By the time their first child, Benjamin, was an adult, people began to pronounce their Wolof surname as Banneker.
At age 57, Benjamin Banneker started calculating astronomical events. In 1791, Banneker published his first almanac and assisted Andrew Ellicott in surveying what would become Washington, D.C. Academic clubs, a stamp, schools, parks and other public properties throughout America are named for Banneker. He never married.