三国史記 (History of the Three Kingdoms — Oldest surviving Korean history, 1145)

...the daughter of Galsun King Ilji. One source says the queen's surname was Park. Originally, when Namhae passed away, Yuri was supposed to take the throne, but because the Grand Assistant Talhae possessed great virtue and prestige, he yielded the throne to him. Talhae said, "The divine vessels and great treasures are not for an ordinary person to bear. I have heard that sages and wise men have many teeth; we should test this by having them bite a rice cake." Yuri's teeth had many marks, so the attendants and ministers honored and installed him. He took the title Isageum. Ancient legends are like this, but Kim Daemun says that Isageum is a local word meaning "teeth marks." In the past, when Namhae was about to die, he said to his son Yuri and his son-in-law Talhae, "After I die, you two of the Park and Seok surnames should succeed to the throne based on seniority." Afterward, the Kim surname also joined the other three, succeeding each other based on age; therefore, they were called Isageum.

In the second year, spring, the second month, he personally performed sacrifices at the Founder's Temple and issued a general amnesty.

In the fifth year, winter, the eleventh month, the king was touring the country and saw an old woman who was starving and freezing to death. He said, "I, in my limited capacity, occupy the highest position but cannot provide for the people, causing the old and young to reach such extremes. This is my crime." He removed his own clothing to cover her and gave her his own food. He then ordered the officials in every region to inquire after the widowed, the orphaned, the solitary, and the aged or sick who could not provide for themselves, and to provide them with support. Consequently, the number of people from neighboring countries who heard of this and came to live there was great. In this year, the people were happy and healthy. He first created the Dosolga Song of Tushita Heaven; this song was the beginning of music.