Adolph I of Nassau-Wiesbaden-Idstein

Adolph I (c. 1307–1370) was the eldest son of Count Gerlach I of Nassau and Agnes of Hesse. He and his brothers took full power when their father abdicated in 1344, ruling jointly until they partitioned the inheritance in 1355. Adolph thereby founded the Nassau-Wiesbaden-Idstein line and resided chiefly at Idstein, where he built the Hexenturm.

In imperial politics he supported Emperor Charles IV. In 1322 he married Margaret of Nuremberg, daughter of Burgrave Frederick IV.