unified Silla: Silla since 676 AD, when the Silla Kingdom unified the three kingdoms of the Korean Peninsula; the Silla Kingdom defeated the Baekje and Goguryeo Kingdom, in a joint attack with the Tang Dynasty of China, and unified the three kingdoms after driving out the Tang army; the Unified Silla Kingdom collapsed when it surrendered to Wang Geon of the Goryeo Dynasty in 935 AD.