Dorothea was born on Friedrichsfelde Palace near Berlin, the fourth and last daughter of Duchess Dorothea of Courland, who was by then separated from her husband, Duke Peter of Courland.
Dorothea s-a născut la Palatul Friedrichsfelde în apropiere de Berlin ca a patra și ultima fiică a Ducesei Dorothea de Courland, care era atunci separată de soțul ei, Ducele Peter de Courland.