Complex sentence: In 1918, he returned to Palestine and served as the personal secretary of the Edah HaChareidis, under Rabbi Yosef Chaim Sonnenfeld, where he published his famous work "Ketzos HaShulchan" in 1926.
Split into simpler sentences: In 1918, he returned to Palestine and served as the personal secretary of the Edah HaChareidis, under Rabbi Yosef Chaim Sonnenfeld,. He published his most famous work "Ketzos HaShulchan" in 1926.