רבנו אשר – ר’ אשר בן יחיאל – רא”ש – R. Asher b. Yechiel – Rabbenu Asher – c. 1250-1327 – Primarily known for his responsa, Rosh was already an acknowledged leader of German Jewry when he fled persecution, settling in Toledo, Castile (in present-day Spain). The Rosh’s immigration from Ashkenaz to Sefarad was impactful…