Sheikh Hasan Ma'shum (1884–1937) served as Mufti and Qadhi of the Deli Sultanate, bearing the honorific "Imam Paduka Tuan." He taught at the Masjid al-Haram in Mecca and was regarded as an authority in Shafi'i jurisprudence and Sufism. He was the teacher of the generation of ulama who founded North Sumatran organizations such as Al-Washliyah and Al-Ittihadiyah. His grave lies in the courtyard cemetery of the Grand Mosque of Medan (Al-Mashun), beside the Deli palace, and is visited by pilgrims.