In the Dynastic cycle, the Qin and Tang Dynasties of ancient China showed similar periods of Decline. For Example, they at one point care about there people. Another example, They were both weak from hunger and the dynasty did not care. Also, they both dynasties were conquered at one point. People were dying because under control. These are the way how Qin and Tang were similar.
There are some differences to with Qin and Tang. First, Qin didn’t care about his army he would let them die. No army then the dynasty would die from no military.