History of Cheju-do

It has also been claimed that three brothers including Ko-hu who were the 15th descendants of Koulla, one of the Progenitors of the Jeju people, were received by the court of Sillaat which time the name Tamna was officially recognized, while the official government posts of Commander, Prince and Governor were conferred by the court upon the three.

However, there is no concrete evidence of when the "Three Names" (Samseong-Ko, Yang and Pu) appeared nor for the exact date of when Ko-hu and his brothers were received by Silla. It may be supposed that the founding Period by the "Three Names" occurred during the Three Kingdoms (Goguryeo, Baekje and Silla) period on the mainland of Korea.

Taejo, founder of Goryeo, attempted to establish the same relationship between Goryeo and Tamna as Tamna had had with Silla. Tamna refused to accept this position and the Goryeo court dispatched troops to force Tamna to submit. Ko ja-gyeon, chief of Tamna, submitted to Goryeo in 938 and sent his son, Prince Mallo, to Goryeo's court as a de facto hostage