In 1306 he founded the side-line Hachberg-Sausenberg at Sausenburg Castle, a castle which the Margarves of Hachberg had built in 1240 on top of Mount Sausenberg. In 1311 Lord Lüthold II of Rötteln made Rudolf his co-ruler at Rötteln Castle. This established the foundation for the rise of the Hachberg-Sausenberg line.
Rudolf himself died before Lüthold. In 1315, Lüthold donated the Lordship of Rötteln to Rudolf's son Henry, who came of age in that year.