Loránd Eötvös
Haar was born to a Hungarian-Jewish family in Budapest on 11 October 1885 to parents Ignác Haar and Emma Fuchs. He graduated in 1903 from the secondary school Fasori Evangélikus Gimnázium where he was a student of László Rátz. He started his university studies in Budapest, later moving on to Göttingen reading Mathematics and sciences. Among the many famous professors he was taught by, he could count Loránd Eötvös, József Kürschák, Constantin Carathéodory, David Hilbert, Felix Christian Klein and Ernst Zermelo.