A founding scholar of Nahdlatul Ulama, renowned for his mastery of fiqh. Born on 18 September 1886, he founded Pesantren Mamba'ul Ma'arif (Denanyar) in Jombang and pioneered pesantren education for female students in Indonesia. He became Rais Aam of NU in 1972. He died on 25 April 1980 at age 93 and is buried on the north side of the Denanyar mosque. He was the grandfather of President Abdurrahman Wahid (Gus Dur).