a German-Hungarian astronomer, maskil, mathematician, and rabbi. Friesenhausen was one of the first proponents of Torah im Derech Eretz, a philosophy of Orthodox Judaism that formalizes a relationship between traditionally observant Judaism and the modern world. He proposed a dual curriculum of Jewish and secular studies for all rabbinic candidates, a radically innovative idea at that time. Friesenhausen wrote Mosedot Tebel and Kelil Heshbon. In the former, Friesenhausen writes in support of the Copernican heliocentrism, one of the first Jews to do so. In 1796, Friesenhausen published his first book, Kelil Heshbon a Hebrew language manual on algebra and trigonometry
