Silla
Silla was founded by King Park Hyeokgeose in 57 BC, around Gyeongju in the southeast part of the Korean peninsula. Although Silla was founded earlier than Goguryeo and Baekje which coexisted with Silla during that time, it took more time for Silla to build firm government structure than those kingdoms. However, around the 6th century, by accepting Buddhism, Silla made its royal power stronger. Around the 7th century, Silla acquired the Han river area, which was the most important area in Korean history. Finally, Silla conquered Baekje in 660 and Goguryeo in 668, with the Tang Dynasty of China as an ally.