Yongzheng was the one of three famous kings in Ching Dynasty. Another two were his father Kangxi and his son Qianlong. Yongzheng did not live long and died at fifty three, Kangxi sixty eight, Qianlong eighty eight, the longest life in the history of all Chinese kings.
Kangxi came to throne at eight years old by the support of his grandmother and he was in the throne of sixty one years, but Yongzheng only thirteen years, Qianlong sixty years.
Kangxi was a powerful king and he united the whole China and at that time, he conquered Taiwan into Chinese territory.
Yongzheng did not do much in military expansion, but he did a lot in preventing his Government officers from being bribed. Death penalty would be imposed on the officer if he received bribe by his power.
Qianlong was a king of pleasure. His grandfather laid down a strong foundation of military strength and his father established a good system in political administration. Qianlong just spent his life mostly in sight-seeing from visiting many parts of China where the scenery was beautiful.
Why Yongzheng died so young at fifty three. It was because he worked extremely hard in order to protect his throne form the threat of his brothers who also intended to take the throne from Yongzheng. His health became very bad due to his over-work day and night. He died with much regret of not completing many things he wished to do.