In the final months of 1795, Sophie began to suffer declining health due to a liver tumor that was thought to be caused by tuberculosis. As a result she underwent liver surgery in Jena, which was performed without anesthesia. In January 1797, Novalis was appointed auditor to the salt works at Weissenfels. To earn a stable income for his intended marriage, he accepted the position and moved to Weissenfels to assume his duties. Sophie, on the other hand, stayed with her family. Sophie once more became extremely ill, during which time Novalis's parents finally relented and agreed to the couple's engagement. However, two days after her fifteenth birthday, Sophie died, while Novalis was still in Weissenfels. Four months later, Novalis's brother Erasmus, who had been diagnosed with tuberculosis, also died. The death of Sophie, as well as his younger brother, affected Novalis deeply. Their deaths catalyzed his more intensive commitment to poetic expression. Sophie's death also became the central inspiration for one the few works Novalis published in his life time, the "Hymnen an die Nacht" "(Hymns to the Night)"