JOSKO (or Jossko; end of 15th–beginning of 16th century), wealthy Jewish merchant in Lvov. He was a customs duties collector and a banker to King Alexander of Poland (1501–06), and for many years was a purveyor of cloth and fur to the court. In 1503, as a result of Josko's intervention, the king ordered that the Jews of Lvov be permitted to trade at fairs and the town's markets, despite vigorous opposition from the townsmen. Josko assisted the community against them on several occasions.
Russko-yevreyskiy arkhiv, 3 (1903), nos. 30–35, 47, 48; I. Schipper, Studya nad stosunkami gospodarczymi Żydow w Polsce podczas średniowiecza (1911), 201; M. Balaban, in: Kwartalnik Historyczny, 25 no. 2 (1911).