Emperor Wen of Sui was the founder and first emperor of the Sui Dynasty which reunified China in 589 after centuries of division. As a Northern Zhou official, Yang Jian seized power as regent when Emperor Xuan died in 580 and later established the Sui Dynasty, becoming its first emperor. During his reign, the Sui Dynasty prospered economically and militarily as Emperor Wen defeated threats from neighboring tribes and the construction of the Grand Canal began. He encouraged the spread of Buddhism and had relatively few concubines compared to other Chinese emperors.