Emperor Taizu reigned for seventeen years and died in 976 at the age of 49. Curiously, he was succeeded by his younger brother, Zhao Kuangyi (Emperor Taizong), even though he had two grown sons – Zhao Dezhao, the Prince of Yan (951–979), and Zhao Defang, the Prince of Qin (959–981). The traditional historical accounts place emphasis on the role Zhao Kuangyin's mother played in the decision which was made shortly after the Song dynasty was proclaimed (around 961). So for nearly his entire reign, it was known and accepted that Zhao Kuangyi would succeed him.