In ancient times, in addition to a piece of paper wedding letter still need other epistles

Neither the Tang Dynasty's Book of Intercourse and Book of Answer to Marriage, nor the Song Dynasty's Cursive Post and Dingtai, is a marriage certificate issued by the government, but rather is signed by agreement between a man and a woman, and is more like a prenuptial agreement. Moreover, the contracting parties to it were not actually the couple themselves, but the whole family or even clan represented behind the couple. Having exchanged the finalized post means that the marriage between the Pan and Zheng families, has the force of law. If, after the marriage is concluded, it is found that the other family's situation does not match what is stated in the wedding invitation, it can be used as a basis for repentance or divorce.

Exchanging marriage certificates does not mean the marriage is complete. Ancient people paid attention to the sense of ceremony, which must be welcomed at an auspicious time to complete the wedding and widely publicized before the marriage can be considered a real marriage. And from the betrothal to the process of marriage, despite the marriage certificate as a guarantee, there will be some moths. So five years do not marry, the marriage certificate is invalid.