E. Singer (Xylographische Anstalt) · Public domain

Samson Raphael Hirsch built the intellectual framework for what became modern Orthodox Judaism, arguing that Torah observance and full engagement with secular society were not just compatible but complementary — a philosophy known as Torah im Derech Eretz. After serving as a rabbi in Oldenburg, Emden and as chief rabbi of Moravia, he spent his last decades, from 1851 on, leading Frankfurt's secessionist Orthodox community and publishing his ideas in the monthly journal Jeschurun. He wrote several influential books and was a vocal critic of the Reform and early Conservative movements taking shape around him.