Unified Silla
Unified Silla,or Late Silla, is the name often applied to the historical period of the Korean kingdom of Silla after its conquest of Goguryeo in 668 AD, which marked the end of the Three Kingdoms period. In the 7th century, a Silla–Tang alliance conquered Baekje in the Baekje–Tang War. Following the Goguryeo–Tang War and Silla–Tang War]] in the 7th century, Silla annexed the southern part of Goguryeo, unifying the central and southern regions of the Korean peninsula.
Unified Silla existed during the Northern and Southern States period at a time when Balhae controlled the north of the peninsula. Unified Silla lasted for 267 years until it fell to Goryeo in 935 during the reign of King Gyeongsun.
Through close ties maintained with the Tang dynasty, Buddhism and Confucianism became the principal philosophical ideologies of the elite as well as the mainstays of the period's architecture and fine arts. Its last king, Gyeongsun, ruled over the state in name only and submitted to Wang Geon of the emerging Goryeo in 935, bringing the Silla dynasty to an end.
Further reading
Unified Silla, Wikipedia