This is the interesting thing about history!
History is often full of coincidences!
Emperor Taizong was the great-grandfather of Emperor Ming. In the more than half a century from Emperor Taizong to Emperor Ming, the Central Government of the Tang Dynasty experienced the most disastrous 60 years since the founding of the People's Republic of China. During this period, many palace coups took place, and countless members of the Li Tang royal family were killed and released. The most important one was Wu Zetian's change of Tang Dynasty to Zhou Dynasty. She successively killed several of her sons and daughters, and made more changes to other clans and relatives. He was killed without blinking an eye.
After King Luling was restored to power, Empress Wei took over the affairs of state exclusively and committed adultery with ministers, bringing the court into a state of chaos. Although Emperors Zhongzong and Ruizhong had strong mothers, they themselves were very weak (cannot be said to be incompetent), so until Ruizhong, the Tang Dynasty still could not see any improvement.
It was only after Xuanzong ascended the throne that the Tang Dynasty showed its second spring. Xuanzong is indeed one of the most heroic kings in Chinese history. It was in his hands that the Tang Dynasty truly entered the world. Later, the world's impression of China's prosperity was established during the Xuanzong period. Just because he had taken away his children and wives and caused the Anshi Rebellion, later generations have discounted his evaluation.
We can learn some lessons from Tang Xuanzong. For example, he ascended the throne at the age of 28. He was always wise and capable in his youth, but why did he almost lose his country in his later years? The reason is that he is too old. He has been in power for 43 years and the world has been at peace for a long time. He has relaxed his vigilance, indulged in sensuality, cannot listen to advice, is self-righteous, refuses to admit his mistakes, etc.
As for the other emperors, they basically all have two-character names, because emperors are very particular about naming and cannot be chosen casually. Even if you already had a name when you were king, if you later changed positions or even became emperor, you would have to change your name again. Many of them are taken from ancient books, such as the Book of Changes, etc., such as the character Heng of Suzong Li Heng.