Original: The first Duchy of Saxe-Eisenach was created in 1596, on the death of Johann Frederick II of Saxe-Coburg-Eisenach, for his younger son, Johann Ernst.
Simplified: The first Duchy of Saxe-Eisenach was created in 1596 for Johann Ernst, younger son of Johann Frederick II of Saxe-Coburg-Eisenach.