Judah Leib ben Isaac of Szydłów (Szydłowski) (Hebrew: יהודה לייב בן יצחק משדלוב; d. 1730) was an 18th-century Polish rabbi who served as a representative of Kraków in the Council of Four Lands.
His father Isaac ben Samuel Zak (Zera Kodesh) was the Chief Rabbi of Przemyśl and later Kraków.
His mother was the daughter of Joshua Höschel ben Joseph, Meginei Shlomo and thus was a descendant of Judah Leib the Elder and Rabbi Moses Isserles.
Zak is an abbreviation of the Hebrew expression Zera Kodesh meaning holy seed taken from the verse 6:13 in the book of Isaiah.
[3][4][5] In his early years, Judah officiated as rabbi in Szydłów later serving as representative of Kraków in the Council of Four Lands.