24/06/2022 · In Altenburg on 24 October 1636, Ernst married his cousin Elisabeth Sophie of Saxe-Altenburg. As a result of this marriage Saxe-Gotha and Saxe-Altenburg were unified, when the last duke of the line (Elisabeth's cousin) died childless in 1672. Ernst and Elisabeth Sophie had eighteen children: Johann Ernest (b. Weimar, 18 September 1638 – d.