According to emile durkheim, gives groups social solidarity because members of a group feel they are part of one society

I believe the asnwer is: collective consciousness
collective consciousness would make members of society feel more united because it tend to give them with one same purpose.
For example, despite the fact that the reason horrible, we could see Nazi Germany as a society that had a solid collective consciousness to make their nation and race become the most superior in the world.

Ongoing civil wars western roman empire finally collapsed476 c.e. romulus, the last of theroman  emperors in  the west, was overthrown by the germanic leader odoacer, who became the first barbarian to rule in rome. the order that the  roman empire  had brought towestern  europe for 1000 years was no more.