Professor Alexander Marx's enduring influence on Conservative Judaism emerged not through explicit teaching, but through the quiet power of scholarly example and institutional legacy. At his 70th birthday celebration in 1948 at the Jewish Theological Seminary of America, Rabbi Simon Greenberg delivered a commemorative address that traced Marx's twin impacts: establishing rigorous standards for Jewish historical scholarship and transforming the Seminary's library into a world-class research institution. Drawing on personal narrative and institutional records, Greenberg chronicles his evolution from a skeptical Teachers Institute student - more invested in modern Hebrew literature and Zionism than traditional Wissenschaft des Judentums - to an admirer of Marx's meticulous historical methodology and vast erudition. The testimonial analysis reveals how Marx's unwavering commitment to factual accuracy and detailed scholarship shaped a generation of Jewish scholars, even as his practical achievements in cultural institution-building belied his scholarly temperament. These contributions represent lasting "facts of Jewish History" that continue influencing Jewish intellectual development, particularly significant amid contemporary concerns about Israel's establishment and Jewish communal welfare.