The House of Palatinate-Simmern (German: Pfalz-Simmern) was a German-Bavarian cadet branch of the House of Wittelsbach. The house was one of the collateral lineages of the Palatinate. It became the main branch in 1559. The Palatinate line of the House of Wittelsbach was divided into four lines after the death of Rupert III in 1410, including the line of Palatinate-Simmern with its capital in Simmern. This line became extinct in 1685 with the death of Charles II. The House of Palatinate-Neuburg line inherited the Electorate. The founder of the line Simmern, Stephen, Count Palatine of Simmern-Zweibrücken is also the founder of the cadet branch House of Palatinate-Zweibrücken and its cadet branches. The rights over the County of Veldenz and a share of the County of Sponheim, transmitted by Stephen's wife Anna of Veldenz, were held by these lineages. The house of Palatine-Simmern, in the person of the 1st elector, Frederick III, were staunch Calvinists. Frederick III was a devout convert to Calvinism, and made the Reformed confession the official religion of his domain by overseeing the composition and promulgation of the Heidelberg Catechism. His support of Calvinism gave the German Reformed movement a foothold and base within the Holy Roman Empire. It was also part of the appeal of Frederick V to the Bohemians in electing him King. As of 2022, those in the line of succession to the British throne are Protestant descendants of Sophia, who was born into the house (daughter of Frederick V and Elizabeth Stuart) as Princess palatine of the Rhine, later becoming Electress consort of Hanover Source: Wikipedia (en)