Yaakov Koppel ben Tsvi Margoliyot (d. 1673(?)) was Polish preacher and moralist of the 17th century. He came from Vladimir, Volhyṇia, where he was an eye-witness of the massacres of 1648-49, from which he escaped to Germany. He was the author of Mar'ot Ya'aḳob, tables of ethical rules (Venice, 1662); Mizbaḥ Ya'aḳob, a sermon on penitence and some haggadic novellæ (ib. 1662); and Ḳol Ya'aḳob, on the Pentateuch and the Talmud, to which is appended an elegy on the victims of the above-mentioned massacres (Amsterdam, 1708). (via this article in the 1906 Jewish Encyclopedia)