Before the Chongzhen Emperor died, he naturally knew what was going on for his princesses after the fall of the dynasty. In order to save his daughter from insults, he had to swing the sword in his hand and kill his own daughter, really not because he was too cruel, but because this was the life of those subjugated princesses.
Whenever there was a change of dynasty, in order to show their resentment towards the previous dynasty, the princesses were often not easily killed, but were humiliated and died. This situation especially occurred very frequently during the Period of Great Secession, such as the Five Dynasties and Ten Kingdoms, the Wei and Jin Dynasties, the Southern and Northern Dynasties, the Wuhu Chaohua Period, etc. In those dynasties, if the last princess could die in the rebellion, it would be a blessing.
In addition to being killed, there is also an end that is to marry an enemy. For example, after the fall of the Han Dynasty, several daughters of Emperor Xian of Han all married to The Cao Wei Emperor Cao Pi, and even when the Sui Dynasty fell, the princess also married to Li Shimin's harem, and also gave birth to several dragon sons. Although such a princess rarely suffers from flesh and skin, but serving enemies who have a family and a hatred for the country all day long, this taste is actually not much better than death, it can only be said to be alive.
There is a third outcome that is the most tragic, that is, to become a slave or a military prostitute. In the ancient feudal society, the female relatives of the imperial family were generally pulled to be slave girls, for example, the princesses of the fallen kingdom in the Northern Qi period became slaves, slaughtered by others, and some were humiliated and sold, which was completely indistinguishable from livestock. One of the more typical is the Northern Song Dynasty, when dozens of daughters of Emperor Huizong of Song were all sent to the Huanyi Courtyard of the Northern Jin Dynasty, which was actually a place for soldiers to enjoy themselves, and eventually all of them were tortured to death.
Therefore, for the princess, the subjugation of the country represented a terrible nightmare, and it was precisely because of this that the Chongzhen Emperor killed his concubines and princesses before hanging himself. Killing his daughter with his own hands is a helplessness and pain that only Chongzhen himself knows.