Friedrich Ludwig Gottlob Frege was his full birth name. Little is known about his childhood. Karl Alexander Frege, his father, and Auguste (Bialloblotzsky) Frege, his mother, both worked at a girl's private school built in part by Karl. The family lived at Einheit 9, an apartment building near the university campus. There are no records of any siblings. He entered the University of Jena at the age of 17, where he studied philosophy under Gottlob Frege. After graduating in 1879, he spent the next two years as an assistant to Frege at the University of Berlin. In 1881 he returned to Jena as a lecturer in logic. Two years later he was appointed associate professor and in 1889 full professor. He remained at Jena until his death at the age of 53. His body was brought back to Freiburg for burial in the Friedhof der Kunstfreunde. A statue in his memory stands on the university campus. Frege is best known for his work on formal logic. He proposed the first clear distinction between propositions that describe facts and those that express judgments or opinions. He also developed a notation system for arithmetic expressions that has been used ever since. But he is also noted for his contributions to philosophy of language, mathematics, and psychology. He is regarded as one of the founders of modern logic.