Frederick IV, Elector Palatine of the Rhine (German: Friedrich IV.; 5 March 1574 – 19 September 1610), only surviving son of Louis VI, Elector Palatine and Elisabeth of Hesse, called "Frederick the Righteous" (German: Friedrich Der Aufrichtige; French: Frédéric IV le juste).
Louise Juliana of Orange-Nassau (31 March 1576 in Delft – 15 March 1644 in Königsberg) was a countess consort of the Palatinate by marriage to Frederick IV, Elector Palatine, and took part in the regency government of her son between 1610 and 1614. She also acted as a mediator between the king of Sweden and the elector of Brandenburg in 1631.
Frederick V (German: Friedrich V.; 26 August 1596 – 29 November 1632) was the Elector Palatine of the Rhine in the Holy Roman Empire from 1610 to 1623, and reigned as King of Bohemia from 1619 to 1620. He was forced to abdicate both roles, and the brevity of his reign in Bohemia earned him the derisive sobriquet "the Winter King" (Czech: Zimní král; German: Winterkönig).
Frederick was born in Deinschwang, Palatinate at the hunting lodge (Jagdschloss), Germany. He was the son of Frederick IV and of Louise Juliana of Orange-Nassau, the daughter of William the Silent and Charlotte de Bourbon-Montpensier. An intellectual, a mystic, and a Calvinist, he succeeded his father as Prince-Elector of the Rhenish Palatinate in 1610, and at the age of 17 was married to the Protestant princess Elizabeth Stuart.
Christian I, Prince of Anhalt-Bernburg, also known as Christian of Anhalt, (11 May 1568 – 17 April 1630) was a German prince of the House of Ascania. He was ruling prince of Anhalt and, from 1603, ruling prince of the revived principality of Anhalt-Bernburg. From 1595 he was governor of Upper Palatinate, and soon became the advisor-in-chief of Frederick IV, Elector Palatine.
The Protestant Union (German: Protestantische Union), also known as the Evangelical Union, Union of Auhausen, German Union or the Protestant Action Party, was a coalition of Protestant German states. It was formed on 14 May 1608 by Frederick IV, Elector Palatine in order to defend the rights, land and safety of each member. It included both Calvinist and Lutheran states, and dissolved in 1621.