While her father was a Roman Catholic, Marie Eleonore displayed firm Lutheran sympathies early on. Her father was afraid that she would influence her younger sisters with her religious views, and therefore wished to have her married to someone of her own religious convictions as soon as possible in order to remove her from his domains, and thus considered grooms for his daughter that he would not otherwise have considered.[1]Albert Frederick, Duke of Prussia, the son of Albert of Prussia, was thus accepted as a suitor, despite showing mental disorders.[2] The wedding was conducted in 1573, and Marie Eleonore departed to Lutheran Prussia.
In 1577, her mentally ill spouse was placed under the regency of his cousin George Frederick, Margrave of Brandenburg-Ansbach, which made the position of Marie Eleonore more difficult at the Ducal court of Königsberg.[3] In 1591, she returned with her daughters to Jülich, where she remained until 1592. She arranged the marriage of her daughters to German princes to avoid them being married by the Regency Council to Polish suitors, and by the marriage alliances she arranged, she ensured that the Duchy of Jülich would pass to Brandenburg after the death of her brother.[4]
^R. Scheller, Die Frau am preuß. Herzogshof (1550–1625), 1966 (L, P); Land im Mittelpunkt d. Mächte, Die Herzogtümer Jülich-Kleve-Berg, 1984 (zugleich Ausst.kat. Kleve 1984, Düsseldorf 1985, dort bes. H. Preuß, Pol. Heiraten in Jülich-Kleve-Berg, S. 133-46, P).
^R. Scheller, Die Frau am preuß. Herzogshof (1550–1625), 1966 (L, P); Land im Mittelpunkt d. Mächte, Die Herzogtümer Jülich-Kleve-Berg, 1984 (zugleich Ausst.kat. Kleve 1984, Düsseldorf 1985, dort bes. H. Preuß, Pol. Heiraten in Jülich-Kleve-Berg, S. 133-46, P).
^R. Scheller, Die Frau am preuß. Herzogshof (1550–1625), 1966 (L, P); Land im Mittelpunkt d. Mächte, Die Herzogtümer Jülich-Kleve-Berg, 1984 (zugleich Ausst.kat. Kleve 1984, Düsseldorf 1985, dort bes. H. Preuß, Pol. Heiraten in Jülich-Kleve-Berg, S. 133-46, P).
^R. Scheller, Die Frau am preuß. Herzogshof (1550–1625), 1966 (L, P); Land im Mittelpunkt d. Mächte, Die Herzogtümer Jülich-Kleve-Berg, 1984 (zugleich Ausst.kat. Kleve 1984, Düsseldorf 1985, dort bes. H. Preuß, Pol. Heiraten in Jülich-Kleve-Berg, S. 133-46, P).