After the death of Prince Bethlen Gábor in 1629, his young wife, Catherine of Brandenburg was the Princess of Transylvania for 10 months.

Read more about her reign and find out how she helped eventually Rákóczi György to gain the throne of Transylvania, based on the research of Szibler Gábor:

https://www.hungarianottomanwars.com/essays/catherine-of-brandenburg-wife-of-prince-bethlen/