Princess Elisabeth Sophie of Saxe-Altenburg

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She was the only daughter of Johann Philipp, Duke of Saxe-Altenburg and Elisabeth of Brunswick-Wolfenbüttel.

In Altenburg on 24 October 1636, Elizabeth Sophie married her kisman Ernst I, Duke of Saxe-Gotha. Two years later (1 April 1639) her father died and was succeeded by his brother, Frederick Wilhelm II.

When her cousin, the duke Frederick Wilhelm III died childless in 1672, Elizabeth Sophie became the general heiress of all the branch of Saxe-Altenburg on the basis of her father's testament (as it was ultimately recognized in law that the Salic Law does not prevent an agnate to will all his possessions to those other agnates of the house he desires to make his heirs, leaving other agnates without; and if those favored agnates also happened to be the testator's son-in-law and maternal grandsons, that's in no way prohibited). The other branch of the family, the Dukes of Saxe-Weimar did not accepted that will, opening a succession dispute.

Finally, Elisabeth Sophie and Ernst's sons received the lion's share of Saxe-Altenburg inheritance, but a portion (a quarter of the original duchy of Saxe-Altenburg) passed to the Saxe-Weimar branch.

When the Duke Ernst died in 1675, his numerous sons divided the inheritance (five eighths of all Ernestine lands) into seven parts: Gotha-Altenburg, Coburg, Meiningen, Römhild, Eisenberg, Hildburghausen and Saalfeld. Of them, Coburg, Römhild and Eisenberg did not survive over that one generation and were divided between the four remaining lines.

Of the four remaining duchies, there are only survived two branches: Meiningen and Saalfeld (who eventually became the house of Saxe-Coburg-Gotha).