Constantin Brunner (1862–1937) was the pen-name of the German Jewish philosopher Arjeh Yehuda Wertheimer (called Leo). He was born in Altona (near Hamburg) on 27 August 1862. He came from a prominent Jewish family that had lived in the vicinity of Hamburg for generations; his grandfather, Akiba Wertheimer, was chief Rabbi of Altona and Schleswig-Holstein. Brunner studied philosophy under a number of prominent scholars, but never completed his doctorate. He established himself as a literary critic, and enjoyed a wide celebrity. In the 1890s, he withdrew from public life to devote himself to writing. He lived in Germany until 1933, when, with the rise to power of the Nazi party, he moved to The Hague, where he died on 27 August 1937.