Sao San Htun (Burmese: စဝ်စံထွန်း, Burmese pronunciation: [saʔ sàɰ̃ tʰʊ́ɰ̃]; 30 May 1907 – 20 July 1947) was the hereditary chief of the Shan State of Mongpawn, and Minister of Hill Regions in Myanmar's pre-independence interim government. He was the son of Sao Hkun Hti the ex-sawbwa with Nang Sein Oo, Sao San Htun had 4 childrens with Mahadewi Sao Khin Thaung, they were Sao Hsè Hom the next sawbwa, Sao Kai Hpa (son), Sao Sunanda (daughter), and Sao Myint Gyi (daughter), He was a signatory to the Panglong Agreement that was the basis for the formation of modern Myanmar. On 19 July 1947, Sao San Htun, along with Aung San and seven others, was shot by gunmen during a cabinet meeting at the Secretariat complex in downtown Yangon.[1][failed verification] He died the next day on 20 July at noon. The date of the assassination, 19 July, is commemorated each year as the Martyrs' Day in Myanmar.