Complex sentence: Kauder became a member of Junge Union in the age of 17,1991 he became Secretary General of Baden-Würtemberg CDU until the resignation of Erwin Teufel 2005.
Split into simpler sentences: Kauder became a member of Junge Union in the age of 17. In 1991, he became Secretary General of Baden-Würtemberg CDU until the resignation of Erwin Teufel 2005.