He appears in Midian at the "Mount of God" (Horeb) dwelling with its priest Jethro, one of whose seven daughters he married, thus becoming the father of Gershom and Eliezer.
In Mainz there settled in the 10th century Gershom, the " light of the exile," who, about 1000, published his ordinance forbidding polygamy in Jewish law as it had long been forbidden in Jewish practice.