Question: What era did the husband of Dorothea of Brandenburg reign?

Context paragraphs:
Pribislav-Henry: Pribislav-Henry (German: "Pribislaw-Heinrich" ; d. 1150) was a Slavic Christian prince and the last ruler of the Hevelli (Stodorani) tribe in the Northern March of Brandenburg.  His reign started, probably supported by the Ascanians, after the prior Hevelli prince Meinfried had been murdered in 1127.  Having no sons of his own, he around 1129 gave the area between Brandenburg and Lehnin to his son-in-law, who was the oldest son of Albert the Bear.  Emperor Lothair III approved the gift and made Albert margrave of the Northern March in 1134.  In 1150, Pribislav Henry died and was succeeded, after a short war of succession, by Albert the Bear.

Dorothea of Brandenburg: Dorothea of Brandenburg (1430/1431 – 10 November 1495) was Queen consort of Denmark (1445–1448 and 1449–1481), Norway (1445–1448 and 1450–1481), and Sweden (1447–1448 and 1457–1464) two times each by marriage to Christopher of Bavaria and Christian I of Denmark.  She served as interim regent during the interregnum in 1448, and as regent in the absence of her second spouse during his reign.

Frederick William II of Prussia: Frederick William II (German: "Friedrich Wilhelm II."  ; 25 September 1744 – 16 November 1797) was King of Prussia, from 1786 until his death.  He was in personal union the Prince-elector of Brandenburg and (via the Orange-Nassau inheritance of his grandfather) sovereign prince of the Canton of Neuchâtel.  Pleasure-loving and indolent, he is seen as the antithesis to his predecessor, Frederick II.  Under his reign, Prussia was weakened internally and externally, and he failed to deal adequately with the challenges to the existing order posed by the French Revolution.  His religious policies were directed against the Enlightenment and aimed at restoring a traditional Protestantism.  However, he was a patron of the arts and responsible for the construction of some notable buildings, among them the Brandenburg Gate in Berlin.

Lange-Taylor Prize: The Lange-Taylor Prize (or Dorothea Lange–Paul Taylor Prize) is a prize awarded annually by the Center for Documentary Studies at Duke University, Durham, NC, to encourage collaboration between documentary writers and photographers.  The prize, that has variously been $10,000 and $20,000 (USD), is named after photographer Dorothea Lange and her husband, writer Paul Schuster Taylor.  It has been awarded since 1990.

Christopher of Bavaria: Christopher of Bavaria (26 February 1416 – 5/6 January 1448) was King of Denmark (1440–48, as Christopher III), Sweden (1441–48) and Norway (1442–48) during the era of the Kalmar Union.

Brandenburg Euthanasia Centre: The Brandenburg Euthanasia Centre (German: "NS-Tötungsanstalt Brandenburg" ), officially known as the Brandenburg an der Havel State Welfare Institute ("Landes-Pflegeanstalt Brandenburg a. H.") was established in 1939 and acted during the Nazi era as a killing centre as part of the Nazi Euthanasia Programme, subsequently referred to after the war as Action T4.

Dorothea of Brandenburg, Duchess of Mecklenburg: Dorothea of Brandenburg (9 February 1420, Berlin – 19 January 1491, Benedictine monastery at Rehna) was a princess of Brandenburg by birth and by marriage Duchess of Mecklenburg.

Princess Dorothea of Courland: Dorothea von Biron, Princess of Courland, Duchess of Dino, Talleyrand, and Sagan, known as Dorothée de Courlande or Dorothée de Dino (21 August 1793 – 19 September 1862), was a Baltic German noblewoman.  Her mother was Dorothea von Medem, Duchess of Courland, and although her mother's husband, Duke Peter von Biron, acknowledged her as his own, her true father might be Polish statesman Aleksander Batowski.  For a long time, she accompanied the French statesman Charles Maurice de Talleyrand-Périgord, whereas she was the separated wife of his nephew, Edmond de Talleyrand-Périgord.

Dorothea von Medem: (Anna Charlotte) Dorothea von Medem (3 February 1761 – 20 August 1821) was born a Gräfin (Countess) of the noble German Baltic Medem family and later became Duchess of Courland (a Baltic region).  Popularly known as Dorothea of Courland after her marriage to Peter von Biron, the last Duke of Courland, she hosted an aristocratic salon in Berlin and performed various diplomatic duties on behalf of her estranged husband.

SMS Weissenburg: SMS "Weissenburg" was one of the first ocean-going battleships of the Imperial German Navy.  She was the third pre-dreadnought of the "Brandenburg" class , which also included her sister ships "Brandenburg" , "Wörth" , and "Kurfürst Friedrich Wilhelm" .  "Weissenburg" was laid down in 1890 in the AG Vulcan dockyard in Stettin, launched in 1891, and completed in 1894.  The "Brandenburg"-class battleships were unique for their era in that they carried six large-caliber guns in three twin turrets, as opposed to four guns in two turrets, as was the standard in other navies.

Supporting paragraphs: Dorothea of Brandenburg Christopher of Bavaria
Answer: Kalmar Union