Joseph Horniblow was one of the sons of Molly Horniblow, and hence an uncle to Harriet Jacobs. On January 1, 1818, aged 12, he was sold in order to settle his master's estate. He lived close enough to remain in touch with his family. He got into a physical fight with his master over a whipping, and fled. He was recaptured, and sent to New Orleans, but escaped to Baltimore. He met up with a Northern-born former neighbor of his old master, Daniel McDowell, who didn't report him. He went to New York and his sailor-brother, Mark, was able to see him there.