In Weimar on 26 May 1555 John Frederick II married his first wife, Agnes of Hesse, Dowager Electress of Saxony. Six months later she suffered a miscarriage and died, on 4 November 1555. In Weimar on 12 June 1558 John Frederick II married his second wife, Countess Palatine Elisabeth of Simmern-Sponheim , daughter of the later (1559) Frederick III, Elector Palatine .
Maria Eleonora of Brandenburg (11 November 1599 – 28 March 1655) was a German princess and Queen of Sweden as the consort of King Gustav II Adolph (Gustavus Adolphus). She was a daughter of John Sigismund, Elector of Brandenburg , and Anna, Duchess of Prussia , daughter of Albert Frederick, Duke of Prussia .