R. Jacob b. Moses Judah London (first half of 18th century), was born in Wesel, Germany, Jacob was taken to London as a child, when his father was appointed cantor there. There are those, however, who maintain he was born in London. When his father died, Jacob settled in Frankfort, where he attended the yeshivah of R. Samuel Schotten. After the fire in the Frankfort Jewish quarter in 1711, London moved to Leszno, Poland, where he became cantor and director of the Jewish school. For several years he lived in Prague, holding the post of inspector of the Talmud Torah schools, but he returned to Leszno in 1728. For the next six years he was engaged in writing an allegorical work, Hista'arut Melekh ha-Negev im Melekh ha-Zafon (Amsterdam, 1737), describing the struggle between the evil and the good inclination. He later traveled to Italy, where he published Meginnei Shelomo (Venice, 1741) by Joshua Heschel b. Joseph of Cracow and Shivah Einayim (Leghorn, 1745), which consisted of halakhic writings by Nahmanides, Isaac Alfasi, Isaac Aboab, Judah de Leon, Isaac ibn Ghayyat, and Abraham Bulat. While on a journey to Piedmont, London was suspected of espionage on account of the Hebrew manuscripts that he had in his possession. In his introduction to Meginnei Shelomo, London mentions that he wrote a halakhic work entitled Pegi'at Ya'akov, which is no longer extant. He also wrote Ez Hayyim, a two-part work on moral precepts that was never published.