 They found first admission with his uncle, the duke Johann Wilhelm of Saxe-Weimar, who took over also the guardianship for the princes -at the same time, he was granted by the Emperor with the lands of his brother Johann Frederick II-.After a short time in Weimar, Johann Ernst, as well as his mother and his brothers, lived in Eisenach and Eisenberg.Later, his uncle Johann Wilhelm of Saxe-Weimar lost the Imperial favour.