Born in the 1790s, Mordecai Barnett was one of John and Miriam Barnett’s six children. The few details known of the family’s story offer a glimpse of movements through the Jewish Atlantic world. John and Miriam were likely both born in Amsterdam. Miriam’s brother, Aaron Levy, was Dutch-born, moved to America in the 1760s and found success as an Indian trader and land speculator in Pennsylvania. John and Miriam’s eldest daughter, Rebecca, was born in Amsterdam in 1791, and in 1811 in London married Hyman Polock. He was a jeweler and became a prominent leader in Jewish civic life in Philadelphia, where Mordecai too settled. Among Rebecca and Hyman’s children were Moses Polock, Miriam Polock Wolf and Isabella Polock Rosenbach.