Yuchi Jiong
In 580, Emperor Xuan, who had by then passed the throne to his young son Emperor Jing (by his concubine Zhu Manyue) and become retired emperor, but who was retaining imperial powers, died suddenly. Yang Jian seized power as regent. It was at that time when Duchess Dugu sent Yang Jian a message that stated, "This is like riding a wild beast. You will not be able to come off of it. You need to fight hard to stay on." After Yang Jian defeated the general Yuchi Jiong, who rose against him after he took power, he had Emperor Jing yield the throne to him in 581, ending Northern Zhou and establishing Sui Dynasty as its Emperor Wen. He created Duchess Dugu Empress and their oldest son, Yang Yong, Crown Prince, while creating their other sons imperial princes and the daughters, including Northern Zhou's Empress Yang, princesses.