First, the system of concubines in the Han Dynasty. In fact, the requirements for identity in the Han Dynasty were not so high. Several queens in the Han Dynasty were born as geisha and maids, and some of them were ruthless and famous in history. In the Han TV series that we often watch, besides the queen, the wife is the highest position, equivalent to other dynasties' concubines, as well as lovers and beautiful women. It's hard to push.
Second, the concubines system in the Sui and Tang Dynasties was more formal in the Sui and Tang Dynasties. At this time, the requirements for concubines are also higher. Basically, they are all daughters of extended families. In the Tang Dynasty, there were only four concubines except the queen, just like the imperial concubine, the Shu concubine, the De concubine and the Xian concubine we often heard in TV dramas. Further down, they were equivalent to concubines, that is, Zhao Yi. In fact, in the harem of the Tang Dynasty, whoever was favored by the emperor had more power. For example, when Wu Zetian first entered the palace, she was just a Zhao Yi, but she was in favor, so even Shu Fei couldn't help it.
Third, during the Song Dynasty, the empress was strict with the harem. The queen is in charge of the harem, and the emperor cannot interfere at will. Therefore, in the Song Dynasty, the empress had a high status, and even the phenomenon of listening to politics appeared. The level of concubines in the harem is also determined by the queen, so it is very difficult to be promoted.