After Shi Hu's death, Hehong surrendered to the Eastern Jin Dynasty, and attempted to take Guanzhong during the internal strife between Later Zhao, and in 350, Gonghong claimed to be the governor of Dadu, the great general, The Great Danyu, and the King of Three Qin at Fangtou, and was soon poisoned by Zhao Shihu's old general Ma Qiu.
In 351, Gong Hong's son Jian Jian (苻健) was proclaimed king at Guanlong, with the capital Chang'an (長安), known historically as Former Qin.
At the beginning of the founding of the people, Jian Jian was afraid that the people of the Central Plains would miss the State of Jin, and in Fangtou he made a call for the Great General of the Jin State to Conquer the West, the Military Governor of Guanzhong, and the Assassin History of Yongzhou; he also sent envoys to the Eastern Jin Dynasty as vassals, in order to ease the contradictions in the Guanzhong region.
In 352, Yongzhou assassinated Shi Duhong at Yiqiu Tun and was killed by the general Zhang Ju (張琚), who established himself as the King of Qin and set up a hundred officials. Jian Jian knew and led 20,000 infantry and cavalry to attack Zhang Ju and behead him. He also sent Zhixiong and Zhijing to lead an army to capture Kwantung, assist Xuchang and the Eastern Jin general Xie Shang in fighting on Yingshui, and the Jin army was defeated. More than half of the casualties were also captured and Zhang Yu and his men returned to Chang'an, and Zhang Yu was given the title of Sikong and Yuzhou Assassin, and the town guarded Xuchang. Gongxiong attacked Wang At Longshang, but Wang Wasou fled to Liangzhou without defeat, and Gongxiong's troops were in Longdong. Former Liang Zhang Chonghua made Wang a general of the Eastern Expedition and sent him to join forces with his generals Zhang Hong and Song Xiu to attack Gongxiong. Zhi Xiong and Gong Jing led an army to defeat them, and the generals Zhang Hong and Song Xiu were captured and sent to Chang'an.
In 354, huan wen, a powerful minister of the Eastern Jin Dynasty, led a large army of 40,000 to attack Former Qin, and Huan Jian sent Gong Xiong to lead 7,000 cavalry to engage Huan Chong at Bailuyuan, Huan Wen's army was defeated, and in addition, Huan Wen had long heard that Huan Wen was going to attack, and had already finished harvesting the wheat in the field, so Huan Wen's army was very short of food, and finally had to retreat.
Crown Prince Gong was shot by a stray arrow because of a battle with Huan Wen, and died soon after, and in 355, Jian Li's son Gong Sheng was made crown prince. On the sixth day of the first month of June of the same year, Jian Jian fell ill, and his nephew Zhi Jing led his troops into the Eastern Palace, wanting to kill Zhi Sheng and stand on his own. When Jian Jian heard of the rebellion, he boarded the Duanmen to deploy troops, and all of His Men dropped their weapons and fled, and Gong Jing was killed.
On June 15, Jian Jian died of illness. Crown Prince Gongsheng succeeded to the throne, but the third son of Gong Jian was cruel and drunk and rogue. He actually killed Gu Ming's chancellor and killed his uncle, and in 357 he was imprisoned by King Jian of the East Sea, deposed as the King of Yue, and strangled to death.
After the death of Gong Jian, Zhi Jian succeeded to the throne, and when Zhi Jian took the throne, Former Qin society was in chaos. Guanzhong was originally a region inhabited by various ethnic groups, and ethnic hatred and killing occurred one after another. Former Qin founded the country in the midst of war, and the legal system was not perfect. It also practiced brutal rule, and floods and droughts have occurred, resulting in the rampant qinchuan and the people suffering unspeakable.
He resolutely created a clear political situation, straightened out the rule of officials, punished lawlessness and arrogance, quelled civil unrest, and implemented a policy of resting and recuperating with the people.
Jian Jian was one of the pioneers among the rulers of the ethnic minorities who migrated inland to advocate Sinicization and promote ethnic integration. He made Former Qin the most rapidly developing, politically clear,the most administratively efficient, the most ambitious, and the most vigorous regime in China at that time.
In 382, Jian Jian successively destroyed Former Yan, former Qiuchi State, and Dai Guo ordered Lü Guang to conquer the Western Regions, which was the second time since the Western Jin Dynasty that the Central Plains regime occupied the Western Regions. Since the qin basically unified the north, the surrounding countries sent envoys to the good.
In 373, when unifying the north, Jian Jian also pointed the spearhead at the Eastern Jin Dynasty.
The Eastern Jin Dynasty Liang sent his son Yang Guang (杨廣) to attack Qiuchi. However, Yang Guang was defeated by the Qiuchi general Yang An, forcing Yang Liang to retreat to the danger. The Former Qin general Yang An also took the opportunity to attack the Eastern Jin Dynasty and attack Hanchuan. Soon, Jian Jian ordered The King of Yizhou to attack Hanchuan and Jianmen, and launched a large-scale attack on Liang and Yi'er Prefectures in the Eastern Jin Dynasty. Yang Liang's resistance failed, and he had to retreat to Xicheng, and as a result, Hanzhong, Jiange, Zitong and other places fell successively. When The Eastern Jin Dynasty's Yizhou assassin Zhou Zhongsun was trying to resist the invading Zhu Weibu in Mianzhu, Mao Dang on the other side had already attacked Chengdu, the capital of Yizhou, and Zhou Zhongsun fled to Nanzhong, so Former Qin captured Yi and Liang Prefectures.
The following year, a rebellion broke out in Yizhou, and the Shu people Zhang Yu and Yang Guang rebelled against Former Qin and claimed the title of Eastern Jin Dynasty, while the Ba Fang chieftains Zhang Zhong and Yin Wan also participated, so Jian Jian ordered Deng Qiang and Yang An to enter Shu to quell the rebellion. The Eastern Jin Dynasty had to return Tobadong County, and Former Qin remained entrenched in Shu Territory.
In 378, the Former Qin General ZhiNan's general Gong Pi and others led 70,000 infantry and cavalry to attack Xiangyang, which belonged to the Eastern Jin Dynasty, and the Eastern Jin Dynasty Liang Prefecture assassin Shi ZhuXu held it for nearly a year, and the city fell and was captured.
In 379 years ago, Qin captured Xiangyang, a strategic town of the Eastern Jin Dynasty, but the attack on Huainan was blocked, and the army attacking Jiangling was also repelled. Jian Jian then decided to redeploy and launch an all-out attack on the Eastern Jin Dynasty. In October 382, Jian Jian gathered his ministers at the Taiji Hall and proposed to personally lead an army of one million to destroy the Jin Dynasty in one fell swoop. Both Murong Chui and Yao Cang of the Qiang dynasty tried their best to support them, but the ministers such as Murong Rong and Shi Yue, the younger brothers of Jian Jian, strongly opposed them. This was because Jian Jian moved Zhu Hu into Guanzhong in order to control it, and also placed the Qi forces at the domestic point to consolidate his power, but this method left the Capital Division empty. Moreover, he was magnanimous, and the monarchs and generals of the enemy countries were all awarded to high-ranking officials, allowing them to lead the old departments, causing hidden worries.
In August 383, Gong Rong led a vanguard army of 250,000. Jian Jian led 600,000 infantry and 270,000 cavalry, a total of 1.12 million troops. The attack on the Eastern Jin Dynasty was the famous "Battle of Shuishui" in history, which ended with the defeat of former Qin.
After the Battle of Shuishui, Former Qin was seriously injured, and the previously unified Xianbei, Qiang and other tribal chiefs raised troops to rebel and established a divided regime. First, Murong Chui fled back to former Yan's homeland to restore the kingdom as king, Murong Lin, Murong Feng, Murong Nong, Murong Long, and others of the Murong clan, who were dressed in horses and armor, and wolf smoke everywhere; Yao Cang and others of the Qiang clan re-emerged; And Zhai Bin, a member of the Ding clan, also rebelled, and the north was once again divided.