As we all know, there were two social systems circulating in ancient China, one was matriarchal system and the other was paternal system. Due to historical reasons, uncle's status is very high, which is reflected in the combination of these two systems. In matriarchal society, everyone only knows who his mother is, but not who his father is. So there is no concept of father. At this time, this feeling will be integrated into the brothers who grew up with them, and the brothers will act as a position and play the role of fathers.
As we all know, in ancient times, the medical level was not that high, so the average life expectancy of people was not very long. So when the daughter gets married, the father may be old, and the strong ones are the woman's brother and uncle. At this time, because men are generally dominant, brothers often play a very important role in women's marriage, which is also a manifestation of a big father like a brother.
Relatives' relatives refer to women's relatives, especially uncles, and can be called relatives. And why not let the uncles who are closer to each other serve at our banquet? It is precisely because these people are in the family that there is a certain competition for inheritance and property, and my uncle, as a consort, can't distribute the property at home, so the natural relationship will be closer.
At the same time, China has been a country of etiquette since ancient times, and my uncle has a greater generation, so it is also in line with our etiquette to let my uncle sit at the dinner table.