To resurrect an old thread.
6.1 The Rise of Qin 2
The man who would become the First Emperor, was according to legend, of dubious birth. The King of Qin became enamoured of the maid of a merchant, Lu Buwei. So Lu, to curry favour with the King, presented her as a present. The two were wedded and a yr later, Prince Cheng was born. In the meantime, Lu manoevered himself into power due to his influence with the King.
Well, the King had many sons I think and Prince Cheng was sent to a state (forgotten which one) as a hostage when he was very young, as insurance for good behaviour fr Qin. He was certainly being viewed as expendable (since he was suspected of being Lu's son, rather than the King's). But this is all legendary stuff and of coz, we know that the Confucians wrote it. Confucians really have a score to settle with the First Emperor. Personally I think he was a real prince by birthright.
Anyway the King died and Lu manoevered to get the prince back to Qin to become the new king (with himself as regent). He had great influence at court and certainly picked this prince cos he had influence with his mother (former maid). So King Cheng ascended the throne and ruled over the mightiest kingdom in China.
By then, Qin had become very powerful. Due to the strict enforcement of Legalist practises (laws and regulations), the Qin was very organised. They struck northwards and westwards, driving the barbarian tribes (pastoralists) into the steppes. This was the time before the horse-riding nomads I think which they would learn in the steppes fr the West. The Qin also conquered Shu and Ba in the south i.e. modern Sichuan and began massive irrigation projects there. These irrigation works are still in use even today.
Coupled with the economic bounty of two agricultural regions, the Qin became unstoppable. They took the religious vessels and rods (or something) fr what remained of the Zhou, effectively ending the Zhou Dynasty. Then they took on the remaining states, felling every one in rapid succession.
And in 221 BC, the last state fell and King Cheng became the new sovereign of China. To herald a new era (to differentiate fr his Zhou predecessors), he styled himself as Qin Shihuang Di. Di meaning emperor, sort of. The Qin was to become the effective blueprint for Imperial China till 1911.
PS - Later on, Lu Buwei was ordered to commit suicide by King Cheng (who was ridding himself of his regent) over some issues (probably to do with his corruption in office). Also note, Li Si, a Legalist, appeared some time now and later became a trusted civil official and pillar for the Qin.
Next - 6.2 The Qin Dynasty