Zhao Heng (趙恆) (968–1022), formally Emperor Zhenzong (眞宗), was the 3rd emperor of imperial China's Song Dynasty. He reigned from his father Emperor Taizong's death in 997 until his own death in 1022, when he was succeeded by his son Emperor Renzong.
Emperor Zhenzong's reign was noted for the consolidation of power and the strengthening of the dynasty. The country prospered, and its military might was further reinforced. However, it would also mark the beginning of a foreign policy towards the Khitan Empire (Liao Dynasty) in the north that would ultimately result in humiliation. In 1004, the Khitan waged war against the Song empire. Zhenzong, leading his army, struck back at the Khitan. Despite initial successes, in 1005 Zhenzong concluded the Shanyuan Treaty. The treaty resulted in over a century of peace, but at the price of the Song dynasty agreeing to an inferior position to the Khitan, and also agreeing to pay an annual tribute of 100,000 ounces of silver and over 200,000 bolts of silk. The admission of inferiority would come to plague the foreign affairs of the Song dynasty, while the payments slowly depleted the empire's coffers.