JERUSALEM (AP) — Israeli leaders are mourning the death of a prominent Hassidic rabbi who survived Auschwitz and championed Holocaust remembrance among ultra-Orthodox Jews.

Thousands attended the Jerusalem funeral of Menachem Mendel Taub, scion of a Hungarian rabbinic dynasty, who died Sunday aged 96. Taub helped produce a two-volume encyclopedia documenting Jewish religious martyrs killed in the Holocaust. His death comes days before Israel marks Holocaust Remembrance Day, honoring six million Jews killed by Nazi Germany.

Israeli Prime Minister Benjamin Netanyahu says that Taub “survived the horrors of the Holocaust and dedicated himself to rebuilding the world of Torah in the State of Israel and among the Jewish diaspora.”

President Reuven Rivlin says on Twitter that Taub’s work “has particular resonance at present as we redouble our commitment to remember and never forget.”