On his deathbed, Emperor Taizong demoted all the capable old ministers around him. Why?

First, protect these old ministers. With the death of the emperor and the replacement of the new leadership, many people will be confused about the situation and stand in the wrong team, which is likely to be purged after the new leadership takes office.

Secondly, it is also to let successors have room to continue to use. Do you think these ministers are already in a position, and the new leader will promote them when he takes office? What room is up there? Of course, the best way is to lock it up first, or demote it, and then bring it up and let it out when the new leader comes. -this also makes those who are fooled feel comfortable.

In fact, these tricks were commonly used by emperors after Emperor Taizong, such as Kangxi Qianlong, because Emperor Taizong's "Emperor Fan" set an example for later emperors.