Polish rabbi of the seventeenth century. His father is styled "ha-Ḳadosh," a term generally given to a martyr, so that Simeon may have been martyred during the massacres instigated by Chmielnicki. Jacob was probably rabbi at Nemirov, where his wife and three sons were murdered in 1648. He then resolved to emigrate to Palestine, but seems to have remained for several years in Venice, where he published his "Ohel Ya'aḳob" (1667), a homily on that part of the Pentateuch which deals with the 'Aḳedah. He left a work, as yet unpublished, entitled "Toledot Ya'aḳob," which contains homilieson the Pentateuch, the preceding work probably being a part of it.