Jacob attended the university first and showed proof of his hard work ethic and quick intelligence. Wilhelm joined Jacob at the university, and Jacob drew the attention of Professor Friedrich Carl von Savigny, founder of its historical school of law. He became a huge personal and professional influence on the brothers. Throughout their time at university, the brothers became quite close with Savigny and were able to use his personal library as they became very interested in German law, history, and folklore. Savigny asked Jacob to join him in Paris as an assistant and Jacob went with him for a year. While he was gone, Wilhelm became very interested in German literature and started collecting books. Once Jacob returned to Kassel in 1806, he decided to quit studying law and instead spent his full efforts on German literature. While Jacob studied literature and took care of their siblings, Wilhelm received his degree in law at Marburg. During the Napoleonic Wars, Jacob interrupted his studies to serve the Hessian War Commission. In 1808, their mother died and it was hard on Jacob because he took the position in the family as a father figure, while also trying to be a brother. From 1806 to 1810, the Grimm family had barely enough money to properly feed and clothe themselves. During this time, Jacob and Wilhelm were concerned about the stability of the family. Achim von Arnim and Clemens Brentano were good friends of the brothers and wanted to publish folk tales, so they asked the brothers to collect oral tales for publication. The Grimms collected many old books and asked friends and acquaintances in Kassel to tell tales and to gather stories from others. Jacob and Wilhelm sought to collect these stories in order to write a history of old German Poesie and to preserve history.