南宋的皇位繼承屢生糾紛，尤以理宗（1205-1264，1224-1264在位）的即位最具爭議性，由此引發的政爭影響深遠。當寧宗（ 1168-1224，1194-1224在位）垂死之際，在宰相史彌遠（ 1164-1233）的策劃下，理宗從原本的皇姪身分變成皇子，並順利承繼皇位。掌權的史彌遠隨即對內徵召理學名士入朝，對外強化控制山東忠義軍，企圖藉著新君即位，修補與異議者關係，創造改善政局的轉機。但是，寶慶元年（ 1225）年初，湖州爆發擁立失勢皇子趙竑（ ?-1225）的事變與忠義軍在楚州的叛亂，嚴重破壞主政者的佈局。為求穩定局勢，史彌遠逼死趙竑、全力安撫忠義軍的作法，引來諸多批評與抗議，最終導致史彌遠與真德秀（ 1178-1235）、魏了翁（1178-1237）為首的反對派徹底決裂，彌遠藉台諫官之力，將這批異議者逐出朝廷。理宗與史彌遠雖斥逐知名理學家，卻仍要提倡其所代表 的學術來吸引士人的向心，以致真德秀等人雖失去官職，仍在民間著書、授徒，擁有極高的聲望。等到山東忠義軍的威脅在紹定四年（ 1231）大致解決，史彌遠放鬆對內的壓制，逐步恢復真德秀等人官銜與職位。只是經過這一段時期的激烈對抗，史彌遠與反對者的關係已難以修補，迨其身故，理宗親政，南宋政局仍繼續在支持與反對史彌遠的兩大陣營衝突中，持續動盪。

As Emperor Ningzong failed to appoint his heir-apparent, his death in 1224 created possible conflicts in the court. By cooperating with Empress dowager Yang, however, prime administer Shi Miyuan successfully enthroned Zhao Yun as Emperor Lizong, and another imperial son Zhao Hong, who had been adopted as Ningzong’s son in 1221, was forced to leave the capital to Huzhou. To strengthen the authority of new emperor, Shi recruited famous Neo-Confucians, such as Zhen Dexiu, to the court, and started to adopt an aggressive policy to control the “loyalist armies” along the northern border. Having controlled the Song court for seventeen years, Shi Miyuan certainly tried to create a turnaround at the time of enthroning the new emperor. His main objective was to receive more support inside, and strengthen the border defenses outside. Unfortunately, two rebellions occurred in early 1225, which not only ruined the plans of Shi Miyuan, but also produced protests from bureaucrats, especially from famous Neo-Confucians. To prevent these protesters from threatening his power, Shi Miyuan convinced the emperor to expel them from the court, which created severe rivalry between Shi Miyuan and Neo-Confucians, such as Zhen Dexiu and Wei Liaoweng. To Emperor Lizong, the policy of Shi created a dilemma. On the one hand, as Shi Miyuan and his supporters had dominated the government for a long time, the emperor needed to accept Shi’s suggestions, but he also wanted to recruit Neo-Confucians to his court, as Neo-Confucianism had become increasingly popular among literati class. This dilemma was the main factor producing the political factions during Lizong’s reign, even after the death of Shi Miyuan in 1233.