In 1741 the branch of Saxe-Eisenach-Jena became extinct with the death of Wilhelm Heinrich, Duke of Saxe-Eisenach. As the only surviving kinsman of the late duke, Ernst August inherited his estates; the union between Saxe-Weimar and Saxe-Eisenach-Jena now became permanent. One of the duke's few wise decisions was the institution of the "Primogenitur" in Saxe-Weimar (confirmed in 1724 by the Emperor Karl VI); this stopped further land divisions in the future. From 1741 his new duchy took the name of Saxe-Weimar-Eisenach (Jena was merged by Eisenach), but the union was by this time only personal. The new state consisted of two larger areas around the two official residences in Weimar and Eisenach, which were not connected, and a patch of smaller areas and towns between them.