Encyclopedia Britannica 11th Edition Vol 1

The part played by the legal fiction of adoption in the constitution of primitive society and the civilization of the race is so important, that Sir Henry S. Maine, in his Ancient Law, expresses the opinion that, had it never existed, the primitive groups of mankind could not have coalesced except on terms of absolute superiority on the one side and absolute subjection on the other. With the institution of adoption, however, one people might feign itself as descended from the same stock as the people to whose sacra gentilicia it was admitted (p. 252)