Usan-guk, or the State of Usan, occupied Ulleung-do and the adjacent islands during the Korean Three Kingdoms period

Three Kingdoms of Korea

The Three Kingdoms of Korea refer to the ancient Korean kingdoms of Goguryeo, Baekje and Silla, which dominated the Korean peninsula and parts of Manchuria for much of the 1st millennium...

. According to the Samguk Sagi

Samguk Sagi

Samguk Sagi is a historical record of the Three Kingdoms of Korea: Goguryeo, Baekje and Silla. The Samguk Sagi is written in Classical Chinese and its compilation was ordered by Goryeo's King Injong Samguk Sagi (History of the Three Kingdoms) is a historical record of the Three Kingdoms of...

, it was conquered by the Silla

Silla

Silla was one of the Three Kingdoms of Korea, and one of the longest sustained dynasties in...

 general Kim Isabu

Kim Isabu

Kim Isabu was a general and politician of Silla during the 6th century. He was also known as Taejong. He is best remembered today for his role in subjugating the island nation of Usan-guk which is known as the Liancourt Rocks or Dokdo Island today. Although frequently referred to as "Isabu", his...

 in 512

512

Year 512 was a leap year starting on Sunday of the Julian calendar. At the time, it was known as the Year of the Consulship of Paulus and Moschianus...

. He is said to have used wooden lions or tigers to intimidate the residents into surrendering. Usan-guk rarely enters into historical records, but appears to have continued a largely autonomous existence until its annexation to Goryeo

Goryeo

The Goryeo Dynasty or Koryŏ was a Korean dynasty established in 918 by Emperor Taejo. Korea gets its name from this kingdom which came to be pronounced Korea. It united the Later Three Kingdoms in 936 and ruled most of the Korean peninsula until it was removed by the Joseon dynasty in 1392...

 in 930

930

Year 930 was a common year starting on Friday of the Julian calendar.- Europe :* With the establishment of the Althing, now one of the world's oldest parliaments, the Icelandic Commonwealth is founded....

.

According to Sejong Sillok, Goryeosa, and Mangi Yoram, Usan-guk consisted of Ulleung-do and Usan-do. Koreans believe Usan-do

Usan-do

Usan-do is a historical name for an island in theSea of Japan described in Korean records. It was part of the ancient state of Usan-guk, but its exact identity is disputed. It may refer to:* Ulleungdo...

 is Liancourt Rocks

Liancourt Rocks

The Liancourt Rocks, also known as Dokdo or Tokto in Korean or in Japanese, are a group of small islets in the Sea of Japan . Sovereignty over the islets is disputed between Japan and South Korea...

(Dokdo in Korea, Takeshima in Japan), although some Japanese scholars dispute the interpretation of some of the records.