Lucas Cranach the Elder - Portrait of Johann the Steadfast, Elector of Saxony. In 1526, Sybille of Cleves, Anne of Cleves older sister, married Johann's eldest son, John Frederich. Johann the Steadfast ruled for another 6 years, and on his death, John Frederick became the Elector. The Electors of Saxony were followers and deeply committed to Lutheranism, Sybille converted to this faith when she married. Her father John III of Cleves was originally against the match, but relented.