At the same time, the She-An Rebellion and Later Jin incursions forced the Ming government to cut funding for the postal service, which resulted in the mass unemployment of men in the provinces hit hard by natural disasters.

By 1627, the war with the Later Jin as well as the eruption of the She-An Rebellion in 1621 had drained Ming treasuries to dangerously low levels, with just seven million taels left in the Taicang Vault.

In 1627 widespread drought in Shaanxi resulted in mass starvation as harvests failed and people turned to cannibalism.

"[2] The Chongzhen Emperor's petty and mercurial ways exacerbated the situation by constantly switching grand secretaries, which prevented a coherent government response from coalescing.

[3] To prevent further depletion of the imperial treasury, Chongzhen cut funding for the Ming postal service, which saw the mass unemployment of large numbers of men from the central and northern provinces around the Yellow River region.

This contributed to the overall deterioration of government control, and the formation of bandit groups which became endemic in the last decades of the Ming.

[4] In the spring of 1628, Wang Jiayin started a revolt in Shaanxi with some 6,000 followers, one of whom was Zhang Xianzhong, who would go on to depopulate Sichuan in the future.

In early 1629 the veteran anti-rebel leader Yang He was called into service and made Supreme Commander of the Three Border Regions.

"[6] When his family disowned him for getting into repeated fights with his peers, he joined the army, which sentenced him to death for breaking military law.

Zhang Xianzhong then joined the rebellion and followed Ma Shouying, who made him a petty officer and named him the "Yellow Tiger".

[6] Eventually hardship struck in the winter of 1631 and Zhang was forced to surrender with Luo Rucai, the first of several times he would do so out of expedience.

[7] At some point Li became an outlaw for killing a man he found in bed with his wife after returning from an extended business trip.

[8] Chen Qiyu was made Supreme Commander of Shaanxi, Shanxi, Henan, Huguang, and Sichuan.

Zhang Xianzhong and Gao Yingxiang were tasked with taking Southern Zhili, Luo Rucai with defending the Yellow River, and Ma Shouying with leading the mobile division.

[8] Zhang and Gao sacked Fengyang, the ancestral home of the Hongwu Emperor and the location of his tomb.

During the operation, a dispute occurred between Li Zicheng and Zhang Xianzhong on whether or not to kill the eunuchs, which led to the dissolution of the rebel alliance.

[8] Zhang Xianzhong failed to take the city of Luzhou, which was heavily defended with cannons that dealt heavy casualties to the rebels, killing 1,100.

Lu was unable to follow up on his victories and he was called back to the northern frontier to deal with the Qing dynasty's invasion.

A new Vice Minister of War, Xiong Wencan, was put in charge of overall rebel pacification activities, but Hong Chengchou and Zuo Liangyu basically ignored all his orders.

Ming forces continued to score victories against Li Zicheng and Zhang Xianzhong without being able to kill or capture them.

At one point Zhang Xianzhong surrendered and was awarded troops and supplies on the promise that he would fight against Li Zicheng.

Joining forces, Zhang and Luo attacked the nearby town of Fangxian and then moved towards the heavily forested mountains of the Shaanxi border.

[8] Although Yang Sichang and Zuo Liangyu clashed on policy, they scored a number of victories against the rebels from 1639 to 1640.

Zuo inflicted a major defeat on Zhang Xianzhong near Mount Manao, killing 3,500 and capturing several commanders.

By the winter of 1640, Sichuan was being ravaged by Zhang Xianzhong, and Ming forces were deserting on a daily basis.

Zhang Xianzhong's army had swelled upward of 100,000 but he was unable to score any major victories against Ming forces except in the taking of cities in Sichuan, which they slaughtered.

By 1643, the rebels had coalesced into two major factions in Li Zicheng in Central China and Zhang Xianzhong in Sichuan.

In Beijing, Chongzhen made a last-ditch effort to raise an army from the civilian population and sent them out against Li.

Li advanced on the Ming capital in two directions, taking Taiyuan, Datong, and Changping in the process.

The next month the northern general Wu Sangui defected to the Qing dynasty, and together they defeated Li at the Battle of Shanhai Pass.