During this dynasty, the architect Yu-wen K'ai redesigned the capital of Ta-hsing, which was renamed Ch'ang-an.  
Its first ruler was defeated by an army led by Ulchi Mundok at Salsu, where almost 300,000 troops were said to have been killed.  That victory saved the Koguryo dynasty, which had been under attack by an emperor who took the throne after assassinating his older brother and his father.  During this dynasty, the architect Yu-wen K'ai redesigned the capital of Ta-hsing, which was renamed Ch'ang-an.  Its last ruler, Kung Ti, ruled for only a year, while its second emperor rebuilt the Great Wall and began to build the Grand Canal system.  After Yang Ti was assassinated, Li Yuan would reunite the empire under the next dynasty.  FTP, name this Chinese dynasty founded by Wen-ti in 581 AD, which unified China for a short time before being supplanted in 618 by the Tang.
Its first ruler was defeated by an army led by Ulchi Mundok at Salsu, where almost 300,000 troops were said to have been killed.  
the Sui dynasty