Jakob Popers held the office of chief rabbi in Frankfurt from 1717 to 1740. Like many of his predecessors, he came from Prague and had previously been a rabbi in Koblenz. He was a Kohen, a member of the tribe of priests, and was thus also named Jakob Katz. Whilst his predecessors only rarely compiled anthologies of religious law, he left the important Book of Responsa, entitled "Sheb Jakob", which was printed in Frankfurt in 1742. A distinctive feature of the book is that it incorporated the discoveries of medical science into religious rulings. During his period of office, the second Fire of the Judengasse occurred in 1721, quickly destroying several of the houses for a second time. In desperation many people sought comfort in Sabbatianism, a messianic undercurrent within Judaism which spread rapidly during that period. Jakob Popers took stern action to oppose adherents of Sabbatianism in Frankfurt: the movement's founder, Sabbatei Zwi, had abandoned Judaism. Popers also fought against the mystical tendencies in the Kabbalah. After a relatively long period of 23 years in office, he died in the Spring of 1740 and was buried by the Gate of Honour in the cemetery in the Battonstrasse.