Emperor Wen of Sui (541-604), personal name Yang Jian, was the founder and first emperor of China's Sui Dynasty (581-618). He was a hard-working administrator. As a Buddhist, he encouraged the spread of Buddhism through the state. Emperor Wen's reign introduced a period of great prosperity not seen since the Han Dynasty. Economically, the dynasty prospered. It was said that there was enough food stored for 50 years. The military was also powerful. At the beginning of his reign, Sui faced the threat of Tujue to the north, and neighboring Tibetan tribes to the west, Goguryeo in the northeast, and the kingdom known as Linyi (Champa) to the south. By the end of Emperor Wen's reign, Tujue had split into an eastern and a western kaganate, the eastern one being nominally submissive to Sui, as was Goguryeo. Linyi was defeated and, while not conquered, did not remain a threat.