 John Ernest, Duke of Saxe-Eisenach

Johann Ernst of Saxe-Eisenach (Gotha, 9 July 1566 – Eisenach, 23 October 1638), was a duke of Saxe-Eisenach and later of Saxe-Coburg.He was the fourth (but second surviving) and youngest son of Johann Frederick II, Duke of Saxony and Countess Palatine Elisabeth of Simmern-Sponheim.