If the queen gives birth to two boys, who should she choose to succeed to the throne? In ancient times, both the backyard of the palace and the nobles attached great importance to the eldest son. In the palace, the eldest son was the first heir. If two sons appear at the same time, it is estimated that there will be a more chilling situation in the fierce harem battle, so in most cases, the emperor will brutally order the execution of a slightly weak constitution, and everyone present will be sealed by the emperor, so there is generally no record of twin princes appearing.
Ancient people attached great importance to geomantic omen, which believed that two stars would collide when they came to earth, which was unfavorable to the national luck. There are almost no records of twins in the royal family because of the eldest son inheritance system. Ordinary people are okay, this is a matter of family property, but the royal family is different, inheriting the whole country. Twins definitely exist in real history, but they are not recorded in history books, and some are simply sent directly to the people to raise them.
Even after the feudal society ended, this idea has not been completely eliminated. In some places, girls in twins will still be sent away, thinking that this is the only way to feed and raise them, so that children who were originally mothers will never see their relatives again in this life. Still too cruel.