Nassau-Idstein

Nassau-Idstein was a Walramian Nassau territory around Idstein and Wiesbaden in the Taunus. In 1337 Count Gerlach I resided at Wiesbaden and ruled the undivided Walramian lands.

The partition of 1355 gave Adolph I a Nassau-Wiesbaden-Idstein line. It adopted the Reformation around 1542 and died out in 1605, leaving its lands to Nassau-Weilburg. A younger line founded in 1629 backed Sweden in the Thirty Years' War, was exiled in 1635 and restored in 1648. After it died out in 1721, Idstein passed through Nassau-Usingen into the Duchy of Nassau in 1806.