Samhan () or the Three Kingdoms of Korea () refers to the three kingdoms of Goguryeo (고구려, 高句麗), Baekje (백제, 百濟), and Silla (신라, 新羅). Goguryeo was later known as Goryeo (고려, 高麗), from which the modern name Korea is derived. The Three Kingdoms period is defined as being from 57 BC to 668 AD (but there existed Gaya confederacy in the southern region of the Korean Peninsula and relatively large states like Okjeo, Buyeo, and Dongye in its northern part and Manchuria of modern China). The "Korean Three Kingdoms" (Goguryeo, Baekje and Silla) contributed to what would become Korea; and the Goguryeo, Baekje and Silla peoples became what we know as the Korean people. The Book of Sui (Volume 81) recorded: "The customs, laws and clothes of Goguryeo, Baekje and Silla are generally identical." The three kingdoms occupied the entire peninsula of Korea and roughly half of Manchuria, located mostly in present-day China, along with smaller parts from present-day Russia. The kingdoms of Baekje and Silla dominated the southern half of the Korean Peninsula and Tamna (Jeju Island), whereas Goguryeo controlled the Liaodong Peninsula, Manchuria and the northern half of the Korean Peninsula. Baekje and Goguryeo shared founding myths which likely originated from Buyeo. Buddhism, which arrived in Korea in 3rd century AD from India via Tibet and China, became the state religion of all 3 constituents of the Three Kingdoms, starting with Gaya in 372 AD. In the 7th century, allied with China under the Tang dynasty, Silla unified the Korean Peninsula for the first time in Korean history, allowing for the first united Korean national identity. After the fall of Baekje and Goguryeo, the Tang dynasty established a short-lived military government to administer parts of the Korean Peninsula. However, as a result of the Silla–Tang War (≈670–676 AD), Silla (joined by Goguryeo and Baekje loyalists) expelled the Protectorate armies from the peninsula in 676 AD. The following period is known as the Unified Silla or Later Silla (668–935 AD). Silla was eventually divided into the Later Three Kingdoms and was ultimately annexed by the new Goguryeo revivalist state of Goryeo. Subsequently, Go of Balhae, a former Goguryeo general or chief of Sumo Mohe, founded Balhae in the former territory of Goguryeo after defeating the Tang dynasty at the Battle of Tianmenling. The predecessor period, before the development of the full-fledged kingdoms, is sometimes called Proto–Three Kingdoms period.