Isabel Rebecca Lyons Mordecai was the daughter of Isaac Lyons and Rachel Cohen and the sister of Henry Lyons. Isaac had immigrated from Oberelsbach in Bavaria and settled in Philadelphia where he married Rachel Cohen, the daughter of Mikveh Israel’s hazzan, Jacob Cohen. Soon after Isabel’s borth, the family resettled in Charleston and moved again to Columbia, where Isaac and his sons opened a grocery. In 1828 Isabel married Moses Cohen Mordecai with whom she raised eight children in their vast Charleston mansion.

Her husband, who would serve as parnass of Beth Elohim, ran a very successful steamship line, whose flagship was named the Isabel. This very steamer carried Major Robert Anderson, Union leader of Fort Sumter, and his garrison after their surrender ended the first, and bloodless, battle of the Civil War. And though Mordecai had initially opposed secession, during the war he was a blockade runner, expending most of his fortune in the service of the Confederacy. After the war he resettled in Baltimore, where he quickly reestablished himself in business and, in 1870, paid for the transfer home of the bodies of South Carolina soldiers who died at Gettysburg.