"Elisabeth Sophie of Brandenburg (5 April 1674 – 22 November 1748), was a Duchess consort of Courland by marriage to Duke Frederick Casimir Kettler of Courland, a Margravine consort of Brandenburg-Bayreuth by marriage to Christian Ernst, Margrave of Brandenburg-Bayreuth, and a Duchess consort of Saxe-Meiningen by marriage to Ernst Ludwig I, Duke of Saxe-Meiningen. She was joint regent in Courland during the minority of her son Frederick William, Duke of Courland from 1698 until 1701." - (en.wikipedia.org 31.01.2020)
