Korean foundation-figure; demigod son of Hwanung (the heavenly prince, son of Hwanin) by Ungnyeo (the bear transformed into a woman). Founded Gojoseon, the first Korean kingdom, traditionally dated 2333 BCE (the 50th year of the legendary Chinese Emperor Yao's reign per Samguk Yusa). Reigned 1,908 years per the literary tradition (Methuselah-syndrome inflation). After his reign, became a mountain spirit (sansin) at Mt. Asadal. The Tangun foundation myth survives in its earliest extant form in the Samguk Yusa (1281 CE), compiled by the Buddhist monk Iryeon during the Mongol-controlled Goryeo period; Iryeon explicitly cites the now-lost Gogi (Old Record) and a now-lost reference in the Wei chronicles. Pai 2000 (Constructing "Korean" Origins) reads the Samguk Yusa's Tangun-opening as a subtle resistance-message asserting Korean origins independent of Chinese authority during the Mongol occupation. Many Korean historians have argued for an etymological identity between Tangun and the Inner Asian Tengri (sky-god). 3 October is celebrated as Gaecheonjeol ("Opening of Heaven Day"), the South Korean national holiday commemorating Tangun's founding. Daejongism (founded 1909) is a modern Korean revival religion centered on the Hwanin-Hwanung-Tangun trinity. North Korea in 1993 announced the "discovery" of Tangun's remains and built a large mausoleum at Pyongyang (1994) — a politically-charged DPRK national-historical monument. The structural classification under the registry: ½ demigod (Hwanung as the divine pantheon-parent + Ungnyeo as the mortal partner — Ungnyeo is bear-transformed-into-fully-human at the time of Tangun's conception).