Isabella Polock was the daughter of Rebecca Barnett and Hyman Polock, German Jews who had settled in Philadelphia in the early 1810s. Born in Amsterdam, they had both moved to London, where they were married by the chief German rabbi, before setting sail for America at the behest of Rebecca’s uncle Aaron Levy. Their last child, Isabella, was born on November 26, 1834.

They became members of Congregation Mikveh Israel and were deeply involved with Jewish life in Philadelphia. Polock went to Rebecca Gratz’s Hebrew school and later recalled being tested by Gratz at the Cherry Street synagogue around the holiday of Purim in 1841. Isabella later taught at the school, as did her sisters.

On November 11, 1857, Isabella married Morris Rosenbach, a clothing merchant who had come from Germany over a decade earlier. Despite some early success, Morris ended up losing his business, and times were often difficult for the family.

In spite of financial uncertainties, Isabella was actively involved with the Hebrew Sunday School Society, Hebrew Female Benevolent Society, the Jewish Orphans’ Home, and the congregation in which she had been reared. Morris died in 1885, and Isabella was left to take care of their eight children, including their youngest, Abraham Simon Wolf, who would later in life become America’s most highly regarded manuscript and rare book collector, bibliophile, and antiquarian.