On 14 June 1668, she married again, at age 31, this time Frederick William, Elector of Brandenburg, a widower himself, with whom she had seven children. Out of love for her second husband, she switched from the Lutheran to the Calvinist denomination. Asked by the (lutheran) Prussian Estates about her religious convictions, she gave them a detailed "Confession of Faith" in early 1669, which began with the sentence: "I do not believe what the Pope orders, not even in all the parts that Luther, Zwingli, Beza and Calvin write (...)." She courageously advocated religious tolerance: "(I) leave (...) everyone the freedom of conscience (...)."[1]
Dorothea was a self-confident, brave and enterprising woman. She accompanied her husband on all his campaigns, slept on the battlefields and, as an equal, had a great influence on his politics. He discussed all his plans for the state with her. In that respect she resembled his first wife Luise Henriette of Nassau. In order to ensure the financial support of her four sons, while his son by his first marriage, Frederick I of Prussia, was to inherit the throne, she purchased the fief of Brandenburg-Schwedt in 1670 and enlarged it by the fief of Wildenbruch in 1680. She also had both castles, Schwedt and Wildenbruch, rebuilt after she made efforts to revitalize these large estates economically.
In 1670, she also received an area outside the gates of the then cities of Berlin and Cölln as a gift from her husband. From 1674, a new suburb was planned there, later named after her: Dorotheenstadt.[2] She had the site parceled out, leased and made substantial profits from the building plots. Dorothea is said to have planted the first tree for the new avenue called Unter den Linden in 1680, an avenue lined with linden trees within her settlement, which had become a kind of artificial island by digging a small canal that complemented the baroque city fortifications (the Berlin Fortress). The tree-lined promenade would later become the magnificent boulevard of Berlin. After the Edict of Potsdam, Huguenots, among others, settled in Dorotheenstadt. She founded a shipyard and a paper mill.[3]
In 1673, the Elector acquired the small Caputh Palace near Potsdam for her, where she had a rural manor house expanded and furnished into her pleasure palace. Today it is a museum of the Prussian Palaces and Gardens Foundation Berlin-Brandenburg, whose exhibition provides information about the life and work of Dorothea. While she herself liked to reside in this small palace, she built a very representative palace complex in Schwedt for her sons.
In 1676, she became the commander of her own regiment, and in 1678 and 1692 equipped two fleets for the Brandenburg state. In 1684, Fort Dorothea was named after her, the second fort in the Brandenburg Gold Coast colony in south-western modern-day Ghana, after Fort Fredericksburg, that her husband had acquired.
The suspicion that Dorothea worked towards a division of Brandenburg-Prussia in order to secure an income for her sons or even to cobble together states of their own for them;[4] this is regarded as refuted by historical scholarship, but spoiled her reputation for a long time. This negative perception is based on the fact that some publicists do not base their critical judgments on Dorothea on the primary sources, but on the centuries-old legends that are mainly based on publications after her death, especially by Karl Ludwig von Pöllnitz. Posthumously, the impression was wrongly given that she wanted to make an agreement with France, accepted a division of the country and thus called into question the rise of Prussia to become a great power. There is no question, however, that the Elector's eldest son and successor Frederick I of Prussia harbored at least corresponding fears about his stepmother.[5]
^Adolf Laminski: Das Glaubensbekenntnis der Kurfürstin Dorothea von Brandenburg aus dem Jahre 1669. (The creed of Electress Dorothea von Brandenburg from 1669), in: Uwe Czubatynski (editor): Kirchenbibliotheken als Forschungsaufgabe (Church libraries as a research task), publisher: Degener, Neustadt an der Aisch 1992, ISBN 3-7686-2055-7, p. 79–84.
^Harald Bodenschatz: Die alte und neue City: Dorotheenstadt und Friedrichstadt (The old and new city: Dorotheenstadt and Friedrichstadt), [1]
^"Frederick William of Brandenburg" . Encyclopædia Britannica. Vol. 11 (11th ed.). 1911. pp. 67–68, see final lines. His concluding years were troubled by differences between his wife and her step-son, Frederick; and influenced by Dorothea he bequeathed portions of Brandenburg to her four sons, a bequest which was annulled under his successor.
^Heinrich Jobst Graf von Wintzingerode: Die märkische Amazone Kurfürstin Dorothea von Brandenburg (The Brandenburg Amazon Electress Dorothea of Brandenburg), Göttingen 2012, ISBN 978-3-932313-48-6, p. 41