what if the new wife is the same age as their eldest child - 4 wives?? continued...

You are comparing the society where this took place to the society where you live in. It may sound strange, but morals are different in different societies. It must have been perfectly acceptable and normal to get girls that young get married. In fact, in that society it may have been considered a preferential choice.

And I am not talking about what I consider right and what I consider wrong.