ר׳ יעקב יוסף הכהן מפולנאה

ר׳ יעקב יוסף הכהן מפולנאה (c.1710–1783) was one of the earliest major exponents of Hasidism and the principal literary transmitter of teachings attributed to ר׳ ישראל בעל שם טוב. His origins and early chronology remain obscure, but he served as rabbi of Shargorod before joining the emerging Hasidic circle after 1741. That commitment reportedly cost him his post. From 1752 until 1770 he preached and served in Nemyriv, and in 1770 became rabbi of Polonne, where he remained until his death. His תולדות יעקב יוסף, printed in 1780, was the first Hasidic book to appear in print and preserves hundreds of teachings in the name of ר׳ ישראל בעל שם טוב. Its homiletical theology contrasts sincere, inward worship with status-conscious religious leadership and helped define the new movement publicly. Three further collections expanded this legacy. Because the sources disagree about both ends of his lifespan, the map treats the birth year as approximate and follows the specialist Posen chronology for his death.