A great scholar and Kabbalist of Galicia, who learnt under many of the great Chassidic masters of the time, he produced works on all areas of Jewish study, and was accepted as one of the great leaders of Polish Jewry. Living at the beginning of the period of emancipation of European Jewry, Rabbi Shapiro was a critic and opponent of the Haskalah, a movement of Jews that wished to liberalize Jewish practice, and become fully part of the secular world.