We welcome back Rabbi Elli Fischer who regales us with his historical detective work to piece together an angle to the 18th-19th century umbrella controversy that most readers miss when they study the Noda B'Yehuda (vol. 2, O.C. #30) and Chasam Sofer (O.C. #72). Our discussion serves a perfect case study for how responsa not only inform the study of history, but how history informs our understanding of the responsa.