Question: Who is the maternal grandfather of Albert Iv, Duke Of Saxe-Eisenach?
Sentence (from "John George II, Duke of Saxe-Eisenach"): When his cousin, the young Duke Johann Wilhelm of Saxe- Jena died( 1690) Johann Georg inherited a part of his duchy, because he was compelled to make a divisionary treaty with the Duke Wilhelm Ernst of Saxe- Weimar, his other cousin and brother- in- law of the late duke.
Relevant evidence: No