The "Shaoxing Peace Treaty" was a humiliating and sovereignty-compromising agreement signed between the Southern Song Dynasty and the Jin Dynasty. Before the treaty was signed, the Song army led by Yue Fei held an absolute advantage on the battlefield, even recapturing Kaifeng, the former capital of the Northern Song Dynasty. The renowned Jin general Wuzhu was forced into continuous retreats, and the fierce and skilled Yue Family Army struck such terror into the Jin forces that they trembled at the mere mention of them. Had it not been for the cowardice of Emperor Gaozong, who allowed the treacherous minister Qin Hui to dominate Southern Song politics, Yue Fei would very likely have led his troops on a triumphant march to recover the lost territories of the Central Plains.
Emperor Gaozong of the Song Dynasty, Zhao Gou, ascended the throne amid a time of chaos; the humiliation of the "Jingkang Incident" did not fill him with a burning hatred for the Jin people, but instead left him terrified at the mere mention of the Jin, afflicted with a severe "Jin-phobia." During his thirty-six-year reign, Gaozong consistently sided with the appeasement faction. Regardless of whether the Song army held an advantage or disadvantage in battles against the Jin forces, it never altered Gaozong's subservient attitude toward the Jin state. Had it not been for this, he would not have so readily aligned with Qin Hui, who staunchly advocated for surrender and peace negotiations.
At the height of the Song army's successive victories, Emperor Gaozong colluded with Qin Hui to recall three anti-Jin generals, including Yue Fei, to the capital, stripping them of military command, and then formally began peace negotiations with the Jin Dynasty. During the negotiations, the Southern Song government made repeated concessions, almost granting every demand from the Jin side, ultimately signing the "Shaoxing Peace Treaty" in Jin territory. The treaty's terms were as follows: First, the Southern Song acknowledged vassal status to the Jin Dynasty, and the Jin enfeoffed Zhao Gou as the Emperor of the Southern Song; Second, the two sides redrew their borders, running from the middle reaches of the Huai River in the east to Dasan Pass in the west, with territory north of this line belonging to Jin and south to the Southern Song, which also ceded Tangzhou and Dengzhou to Jin, along with most of Shangzhou and Qinzhou; Third, the Southern Song agreed to pay a large annual tribute to Jin.
Furthermore, the Jin state insisted that the Southern Song execute the renowned anti-Jin general Yue Fei, with Qin Hui willingly acting as the executioner, while Emperor Gaozong raised no objection. The Shaoxing Peace Treaty, at the cost of immense sacrifices by the Southern Song, secured twenty years of peace between the Song and Jin dynasties.
After this, within the imperial court of the Southern Song Dynasty, the power of the appeasement faction grew increasingly strong, leaving no room for officials advocating resistance against the Jin invaders. The young and spirited students at the Imperial Academy were deeply dissatisfied with this situation. Among them, a student named Zhang Bolin wrote: "Fuchai, your father was killed by the King of Yue—could it be that you have already forgotten this irreconcilable blood feud?" When Emperor Gaozong learned of this, he flew into a rage and had Zhang Bolin exiled to military service.
However, no matter how much Emperor Gaozong tried to appease and compromise, he could never find lasting peace. In 1161, Emperor Wanyan Liang of the Jin Dynasty unilaterally tore up the Shaoxing Peace Treaty and launched a massive army southward to attack the Southern Song Dynasty. This time, Gaozong still insisted on seeking peace, which sparked extreme discontent among the Southern Song military and civilians. In the Battle of Caishi, the Song army, under the command of Yu Yunwen, successfully repelled the Jin forces, crushing their plans for a southern invasion. Soon after, under public pressure, Gaozong announced his abdication in favor of Zhao Shen, who became Emperor Xiaozong of Song.
Emperor Gaozong had only one son in his lifetime, named Zhao Fu, but Zhao Fu died at the age of seven, causing Gaozong to weep bitterly. Because Gaozong had spent his early years fleeing and had lost his fertility, he later adopted Zhao Shen from the imperial clan. Zhao Shen was the seventh-generation grandson of Emperor Taizu, Zhao Kuangyin. Most emperors of the Southern Song Dynasty were incompetent and mediocre, but Zhao Shen was relatively capable. Gaozong's choice of him as heir to the throne was perhaps the last good deed he did for the Southern Song.