While the central Song court remained politically divided and focused upon its internal affairs, alarming new events to the north in the Liao state finally came to its attention. The Jurchen, a subject tribe within the Liao empire, rebelled against the Liao and formed their own state, the Jin Dynasty (1115–1234). The Song official Tong Guan (1054–1126) advised the reigning Emperor Huizong of Song (1100–1125) to form an alliance with the Jurchens and their joint military campaign toppled and completely conquered the Liao Dynasty by 1125. However, the poor performance and military weakness of the Song army was observed by the Jurchens, who immediately broke the alliance with the Song and launched an invasion into Song territory in 1125 and another in 1127 when the Jurchens managed to capture not only the Song capital at Kaifeng, but the retired emperor Huizong and the succeeding Emperor Qinzong of Song as well as most of his court. This took place in the year of Jingkang and it is known as the Humiliation of Jingkang. The remaining Song forces rallied under the self appointed Emperor Gaozong of Song (1127–1162), fleeing south of the Yangtze River to establish the Song Dynasty's new capital at Lin'an (in modern Hangzhou). This Jurchen conquest of northern China and shift of capitals from Kaifeng to Lin'an marks the period of division between the Northern Song Dynasty and Southern Song Dynasty.
Although weakened and pushed south along the Huai River, the Southern Song found new ways to bolster their already strong economy and defend their state against the Jin Dynasty. They had able military officers such as Yue Fei and Han Shizhong. The government sponsored massive shipbuilding and harbor improvement projects, and the construction of beacons and seaport warehouses in order to support maritime trade abroad and the major international seaports, including Quanzhou, Guangzhou, and Xiamen that were sustaining China's commerceTo protect and support the multitudes of ships sailing for maritime interests into the waters of the East China Sea and Yellow Sea (to Korea and Japan), South East Asia, the Indian Ocean, and the Red Sea, it was a necessity to establish an official standing navy. The Song Dynasty therefore established China's first permanent navy in 1132, with the admiral's main headquarter stationed at Dinghai. With a permanent navy, the Song were prepared to face the naval forces of the Jin on the Yangtze River in 1161, in the Battle of Tangdao and the Battle of Caishi. During these battles the Song navy employed swift paddle wheel driven naval crafts armed with trebuchet catapults aboard the decks that launched gunpowder bombs. Although the Jin forces boasted 70,000 men on 600 warships, and the Song forces only 3,000 men on 120 warships, the Song Dynasty forces were victorious in both battles due to the destructive power of the bombs and the rapid assaults by paddle wheel ships. The strength of the navy was heavily emphasized after that. A century after the navy was founded it had grown in size to 52,000 fighting marines. The Song government confiscated portions of land owned by the landed gentry in order to raise revenue for these projects, an act which caused dissension and loss of loyalty amongst leading members of Song society but did not stop the Song's defensive preparations.
Although the Song Dynasty was able to hold back the Jin, a new considerable foe came to power over the steppe, deserts, and plains north of the Jin Dynasty. The Mongols, led by Genghis Khan (r. 1206–1227), initially invaded the Jin Dynasty in 1205 and 1209, engaging in large raids across its borders, and in 1211 an enormous Mongol army was assembled to invade the Jin. The Jin Dynasty was forced to submit and pay tribute to the Mongols as vassals; when the Jin suddenly moved their capital city from Beijing to Kaifeng, the Mongols saw this as a revolt. Under the leadership of Ögedei Khan (r.1229–1241), both the Jin Dynasty and Western Xia Dynasty were conquered by Mongol forces. The Mongols were at one time allied with the Song, but this alliance was broken when the Song recaptured the former imperial capitals of Kaifeng, Luoyang, and Chang'an at the collapse of the Jin Dynasty. As the Mongols invaded and conquered Korea, the Abbasid Caliphate of the Middle East, and Kievan Rus' of Russia, the Mongol leader Mongke Khan was killed in 1259 during the Battle of Fishing Town in Chongqing, China. This prompted Hulagu Khan to pull the bulk of Mongol forces out of the Middle East where they were poised to fight the Egyptian Mamluks, instead they would face the Song. By 1276, most of the Song Chinese territory had been captured by Mongol forces. With the Battle of Yamen on the Pearl River Delta in 1279, the Mongols finally crushed the Song resistance, and the last remaining ruler, the child emperor Bing, committed suicide along with the official Lu Xiufu.
译文:
南宋
由于当朝者并没有解决一系列政治分歧，而是将注意力集中在了它的内务上，直至辽国对北方所发动的一些令人震惊的新事件最终引起了当朝者的注意。女真族，作为辽国境内的一个主要部落，因反抗辽国的统治，并建立了自己的国家—金国（1115-1234）。宋朝官员童贯向当朝者宋徽宗进谏与女真族结盟。1125年，与女真族共同发兵挫败并彻底的征服了辽国。然而，通过这些共同的军事行动，女真族看到了宋军的软弱无能、不堪一击，金国立即撕毁了和大宋间的合约，并分别与1125年和1127年对宋发起两次侵略战争，在后一次战争中，金国不仅设法占领了大宋的都城开封，并且俘虏了徽、钦二帝，以及大部分宗室、官员。这些事情发生在靖康年间，故被称为靖康之耻。宋高宗（1127-1162）称帝并率领余部逃至江南，确立临安（今杭州）为宋朝新的都城。至此，女真族征服中国北方地区，宋朝都城由开封迁往临安成为北宋和南宋的分界线。
尽管宋朝实力受到削弱以至南迁到淮河一线，可南宋却通过革新巩固既有的强大经济以及抵御金国的入侵。
他们拥有岳飞、韩世忠等杰出的军事将领。
政府鼓励大型船厂及码头的改造以及灯塔、港口的建设从而支持海外贸易，诸如泉州、广州和厦门等这些国际性港口对南宋的商业起着支撑作用。
为了保护东海、黄海（朝鲜和日本）、东南亚、印度洋以及红海等水域过往船只的海上利益，必须设立海军机构。
由此，宋朝在1132年建立中国历史上第一支正规海军，并将其总部设于定海。
借助这支正规海军，宋朝于1161年积极备战以应对金国海军渡过长江，并爆发了唐岛之战与采石之战。
在这一系列海战中，宋朝海军充分发挥明轮船的灵活性，并于其配备可以发射火药弹丸的投石器。
尽管金国号称水军70000，战船600，而宋国只有水军3000，战船120；可宋朝依靠炸药的破坏力和明轮船的快捷性取得了两场海战的胜利。
自此之后，海军作战能力被提上日程。然而，100年后人们却发现当时的海军舰队已达到了52000人的规模。
宋廷没收贵族的部分土地以增加税收，虽然此举造成宋朝社会领导层的分歧与离心，却阻止不了宋国备战的决心。
虽然宋国能够阻止金国的南下，可是一个新的、更为强大的敌人出现在金国的北方，他们占领了草原、沙漠和平原。
在铁木真汗的带领下，蒙古人首先于1205年和1209年发动了两次对金的战争，并越过边境对金人进行袭击，1211年的侵略更为强大。
金国被迫投降并向蒙古纳贡称臣。而当金国忽然迁都开封之后，蒙古人将此视为反叛。
在窝阔台（公元1229-1241年）的领导下，蒙古人先后征服了金国与西夏国。
宋国曾一度与蒙古结盟，可是当宋国从覆灭的金国收复昔日的帝国首都开封、洛阳以及北京之后，两国的盟约破碎了。
伴随着蒙古人相继征服朝鲜、中东的阿拔斯王朝以及地处俄罗斯大草原的基辅罗斯，蒙古人的蒙哥汗死于钓鱼城之战（中国重庆）。
旭烈兀汗悲愤交加，将蒙古主力撤出中东，尽管他们应经做好了与埃及马木路克王朝的决战，也只得走上宋国的战场。
截至1276年，宋国的大部分领土已经落入蒙古人之手。
1279年宋蒙于珠江三角洲爆发崖山海战，蒙军一举摧毁了宋军，儿皇帝赵昺亦随着陆秀夫统帅自杀身亡。