They had two children, the eldest Hedwig was born in 1893 while Heinz was born in the following year. Elizabeth Hopf was a Protestant and, in 1895, Wilhelm converted to his wife's religion.
Sila ay dalawang bata ang pinakamatanda Hedwig ay ipinanganak sa 1893 habang Heinz ay ipinanganak sa mga sumusunod na taon. Elizabeth Hopf ay isang Protestante at, sa 1895, Wilhelm iko-convert sa kanyang asawa ng relihiyon.