Zhou Zong's daughter and a year his senior. Lady Zhou was not only highly educated but also multi-talented in music and the arts and the young couple enjoyed a very intimate relationship. Accession to the throne In 955, a year after Li Congjia's marriage, Southern Tang was invaded by Later Zhou. The resistance war did not end until spring 958, after Li Jing ceded all prefectures north of the Yangtze River to his powerful northern neighbor. Li Jing also relinquished all imperial trappings, degrading his own title from emperor to king (). The national humiliation was soon followed by familial tragedy: later that year Li Hongji poisoned uncle Li Jingsui to death, which was followed by his own death a few months later, allegedly hastened by many encounters with Li Jingsui's vengeful ghost. Not long after Li Hongji's death in 959, Li Congjia was given the post of royal secretary () so that he could familiarize himself of governmental affairs. However, despite being the king's eldest surviving son, a few ministers considered him too dissolute and weak for the crown prince position, including Zhong Mo, who pleaded to have Li Congjia's younger brother Li Congshan chosen instead. Li Jing found Zhong's suggestion offensive and demoted him. Suffering from poor health, Li Jing decided to transfer all responsibilities to his successor. He named Li Congjia the crown prince in spring 961 to take over in the capital Jinling (; modern Nanjing, Jiangsu) while he retired to the southern city of Hongzhou (; modern Nanchang, Jiangxi). A few months later he died, and Li Congjia officially succeeded the throne, not without a last-second effort by Li Congshan to challenge him. By then Zhong Mo had also died, so Li Congshan asked chancellor Xu You to bring Li Jing's last will to him. Xu refused and confided in Li Congjia of Li Congshan's intentions. Li Congjia — changing his name to Li Yu — did not punish his younger brother other than a slight demotion. As Southern Tang ruler Appeasing the Song Dynasty A year before Li Yu ascended the throne, Southern Tang's nominal overlord Later Zhou had been replaced by the Song dynasty established by former Later Zhou general Zhao Kuangyin, who had earlier participated in several campaigns against Southern Tang. Knowing the limit of Southern Tang's military strength and trying hard to be subservient to the northern court, Li Yu immediately