Subak can be found in government records from the Goguryeo dynasty through the Joseon dynasty, until the 15th century, after which its popularity declined It reappears only in 1790 book about martial arts titled Muyedobotongji (무예도보통지). It is believed that the warriors from the Silla Dynasty (57 BC-935 AD) known as the Hwarang learned subak from the neighboring Goguryeo armies when they appealed for their help against invading Japanese pirates. But this remains a conjecture, as there is zero actual documentation of such in Korean records. There also remains no known documentation of specific military training by the Hwarang. The development of Subak continued during the Goryeo Dynasty (935–1392). Goryeo records that mention the martial arts always include passages about Subak. The Joseon government, however, outlawed the practice of Subak as a public spectacle in response to problems arising from the betting practices of large numbers of Korean farmers and landowners (these betting practices included wagering land and sometimes family members). Subak disappears in the records of the Joseon Dynasty to make place to Taekkyon. Taekkyon players are portrayed in several paintings from that era. The most famous painting is probably the Daegwaedo (Hangul: 대괘도, Hanja: 大快圖), painted in 1846 by Hyesan Yu Suk (혜산 유숙, 1827–1873), which shows men competing in both ssireum (씨름) and Taekkyon. Goryo period With the Mongol conquest, the Korean military was reorganized around the mounted archer. Armor and weaponry became very similar to Mongol armor and weaponry. Acrobatic horsemanship (masangjae), falconry and polo (Gyeokgu) were imported. The Korean Composite bow (which is very similar to the medieval Mongol bow) was adopted at this time. The unique construction of the Korean Gakgung bow shows the original form of the Mongol bow, before the Manchus improved it with stronger and bigger ears. As the military class in late Goryeo was almost entirely populated by ethnic Mongols in practice, the Joseon Army also carried on the mounted archer tradition. (Yi Seong-gye, the founder of the Joseon dynasty was a hereditary Mongol darughachi of Korean origin, administering the Mongol province of Ssangseong in N.E. Korea. Choi Young made his reputation fighting for the Mongols in northern China, putting down Han rebellions in the last days of the Yuan dynasty.) Until the publication of Muyedobotongji in 1795, archery remained a singular Korean martial art, testable during the military portion of the Gwageo (National Service Examination) Joseon Dynasty Martial Arts