For 10 points,  name this Elector Palatine who briefly became ruler of Bohemia, where he was known as the "Winter King."
This ruler became depressed following an illness acquired at a meeting of the Protestant Union. This person gained one  royal position after John George I refused it. Gabriel I of Hungary supported this person, who faced significant  resentment after the iconoclasm of Abraham Scultetus. The British monarchs are descended from this person's daughter,  Princess Sophia. This person opposed the proposed "Spanish Match" of father- in-law James I. This ruler's reign was  undermined by the Treaty of (*) Ulm, which allowed Christian of Anhalt's defeat at the Battle of White Mountain. After the  Bohemian Revolt, the successful placement of this person on the throne helped instigate the Thirty Years' War. For 10 points,  name this Elector Palatine who briefly became ruler of Bohemia, where he was known as the "Winter King."
This ruler became depressed following an illness acquired at a meeting of the Protestant Union.
Frederick V, Elector Palatine [or Frederick I of Bavaria; prompt on Frederick; accept Frederick the Winter King or Friedrich der Winterkoenig before “Winter King”]