What is the difference in etiquette between marriage and concubinage in ancient times?

In ancient times, a wife had to go through: asking the name, Najib, recruiting relatives, inviting guests, and welcoming guests face to face.

Asking a name: The man asks the woman's name and birthday, which is called asking a name, and it is called "eight-character combination".

Najib: If the name is auspicious, the matchmaker gives a small gift, it is called Najib, and now it is called Guo or Guo.

Levy: Giving gifts such as cash gifts, cakes, gifts and sacrifices is a formal bride price, which is called levy, and now it is called "gift".

Invitation: the man asks the fortune teller to choose a date, which is called invitation, also called "begging for an appointment", and now it is called "choosing a date"

Kissing: The groom takes a limousine to the bride's house to pick her up. This is called kissing.

Concubine: After monogamy is established, only a couple who meet the wedding etiquette can be considered as legal couples.

In other words, concubines don't marry. It is not that weddings are different, but that the latter generally do not get married. Even if there is, it will not be complete.