הרב אברהם בורנשטיין

Avrohom Bornsztain, also spelled Avraham Borenstein or Bernstein, was a leading posek in late-nineteenth-century Europe and founder and first Rebbe of the Sochatchover Hasidic dynasty. He is known as the Avnei Nezer after the title of his posthumously published set of Torah responsa, which is widely acknowledged as a halakhic classic. His only son, Shmuel, author of Shem Mishmuel, succeeded him as Rebbe.