Li Yi, the second son of Li Shimin and Empress Zhangsun, fell gravely ill on the day he was born.
The renowned physiognomist Yuan Tiangang said that Li Yi was destined to face a great calamity. To survive it, he would have to conceal his identity and live a humble life among the people for fifteen years.
And so, Li Yi was sent out of the palace to grow up in poverty in Chang'an, living an ordinary life.
Then one day, Li Yi invented distilled liquor, white sugar, horseshoes, the curved-beam plow, black powder... all kinds of marvelous things.
After that, he noticed that Uncle Qin, who had looked after him since childhood, had become a big talker who kept saying he would give Li Yi a kingdom of his own.
Even Uncle Qin's wife bragged that she would find every unmarried beauty in all of Great Tang and let Li Yi pick his favorite to be his wife.
Faced with this eccentric couple, Li Yi asked, "Since you two are so good at making wild claims, can I become emperor?"
Uncle Qin replied coolly, "How hard could that be?"
