When did the 3 kingdoms of Korea along time ago unite and by what kingdom?

The Three Kingdoms of Korea (Goguryeo, Baekje, and Silla) were united under the rule of Silla in 668 AD. Silla, with the support of the Tang dynasty of China, defeated Baekje in 660 AD and Goguryeo in 668 AD, thus unifying the Korean peninsula.