Goryo was founded by Wang Geon with Songak (present day Gaesong in North Korea) as its capital. Its incoroprated with Shilla in 935 & later destroyed Baekje in 936,reuniting the Korea Peninsula. Goryo’s state religion was Buddhism & its main goal was to enlarge the territory to the North. The later years of the Goryo Dynasty were marred by the invasion of Mongols,who subjugated the Goryo royalty. Barely holding onto its sovereignty,Goryo was able to get it back as China was embroiled in a chaotic struggling between the outgoing Yuan & the coming Ming Dynasty,military officials gained power over the monarchy & the Goryo Dynasty was usurped by Lee Seong-Gye,the founder of Joseon Dynasty. Goryo Dynasty lasted for 474 years.
source : KBS WORLD HISTORY