Saxe-Weimar [SEP] inception
alliance with King Charles IX of France. In 1572 Maximilian II enforced the Division of Erfurt, whereby the Ernestine lands were divided among Duke John William and the two surviving sons of imprisoned John Frederick II. John William retained the Duchy of Saxe-Weimar, while his minor nephews received the southern and western territories around Coburg and Eisenach.
This division was the first of numerous partitions; over the next three centuries the lands were divided when dukes had more than one son to provide for, and re-combined when dukes
John Frederick, Duke of Saxe-Weimar
Duke John Frederick of Saxe-Weimar (19 September 1600 in Altenburg – 17 October 1628 in Weimar) was a Duke of Saxe-Weimar.
Life.
John Frederick was a son of Duke John II of Saxe-Weimar and his wife Dorothea Maria of Anhalt. His brothers were the Dukes John Ernest I "the Younger" of Saxe-Weimar, Frederick of Saxe-Weimar, William IV of Saxe-Weimar, Albert IV of Saxe-Eisenach, Ernest