[1] Diether was the son of Johann II of Katzenelnbogen (died 2 March 1357) and Elizabeth of Isenburg-Limburg.
Diether was married on 8 June 1361 to Elisabeth of Nassau-Wiesbaden-Idstein (died 1 February 1389), a daughter of Adolph I of Nassau-Wiesbaden (1307-1370).
Anna was the last countess of Nassau-Hadamar, and the House of Katzenelnbogen gained possession of Nassau-Hadamar when Anna sold her rights to her stepson Johann IV.
[2] After Diether's death in 1402, his son Johann reunited the upper and lower counties of Katzenelnbogen by virtue of his marriage to Anna, daughter of Eberhard V of the older line of Katzenelnbogen.
This article about a member of the German nobility is a stub.