This is an interesting topic for those who sit within the traditions that find some connection with Abraham – and perhaps more especially the Judea-Christian Traditions.
According to the story Abraham was somewhat advanced in years and his wife Sarah had not conceived. Abraham felt his duty to provide and heir so conceived a child by the servant girl Hagar. The child born was Ishmael and all would have been well, save for the fact that then Sarah conceived and bore a son Isaac. Two mothers and two children is not going to lead to a family without tension! Ultimately this leads to the expulsion of Hagar and Ishmael, a scene beautifully depicted in a Gustaf Dore woodcut with the teardrop in Hagar’s eye.
The promise to Abraham was that he was to be the ‘Father of Many Nations’ and clearly the inference is that in Isaac we have the foundation of Israel and in Ishmael we have the foundation of the Islamic nations. Isaac is clearly the second born.
Isaac had twins, Essa and Jacob. There are two parts to what happens here. Esau was a man of the field, Jacob a more indoors type, and when Esau comes in from the field famished Jacob extracts an exchange of the birthright for a feed. The second option is where Jacob conspires with his mother to impersonate Esau and so gain the blessing from the now blind and dying Issac. Neither story has a lot of moral fortitude. In many senses we are left with the story and it is what it is.
Jacob produced 11 sons before he was renamed Israel (wrestled with God) and then had the twelfth son Benjamin.
In amongst this is the notion of Primogeniture (the first-born male inherits) and the reference in the Jacob and Esau story is one of the very oldest references to it, though in light of his own position it seems a dodgy claim, and fulfilled with a less than intended outcome.
Now whilst accounts recorded some time after the events the relate to, there is generally thought to be some history in the story. But to look even earlier you find the story of Cain and Abel, where it seems that God is happier with the offerings of Abel than he was of Cain and so in jealousy Cain kills his brother Abel. Cain is the younger brother, and yet in punishment God also protects Cain.
We have I think generally become a more egalitarian society, and most wills will distribute the goods and chattels in a more equitable manner, quite often even shares. The challenge of course is the crown. There is only one and it has to go on one head. Most of the monarchies around the world seem to be removing the gender bias of succession, meaning that a first-born girl will likely ascend before a second born male. That is all well and good. Most monarchs are more decorative than functional these days. It is more of a question in families where there is a problem, where maybe the first-born has no talent to run the family company but the second born does. On the one hand you need to have some kind of way of ensuring that the best is done by all, and the decisions sometimes have to be a little more subjective.
Primogeniture is clearly only meaningful when it is convenient.
Given that the religious traditions that have spawned from this would all recognise the value of honesty, integrity, and fairness, you could look at these stories and wonder where those virtues came from. Perhaps there is a serious reminder her that we should not take ourselves too seriously.
The origins of the United Kingdom of Israel are seemingly as murky. The first effort was Saul who reigned for some time, though on his demise Isbaal one of Saul’s sons was proclaimed King. This was turbulent and he was assassinated and Judah ceded from the United Kingdom. David is chosen the youngest of the son’s of Jesse from Bethlehem, by the prophet Samuel. David has a troubled murky life, including sending Uriah the Hittite off to the front line of battle so that David could have his way with Beersheba, Uriah’s wife. None the less David’s was clever in battle, and was able to conquer Jerusalem and very well defended city that had not fallen for a long period, and would not fall again for a long period. This conquest allowed him to re-unite the Kingdom, by moving the capital from Shiloh to Jerusalem. He also moved the Ark of the Covenant here. This meant that neither the north nor the south was compromised, and the old order was restored, and whilst not ruled by the priests, the priest clearly had a good power position with the ark of the covenant installed in the capital.
For those who want a pursue and undefiled religion, where everything is neat and perfect and in order, there is a problem in this kind of background. There is a lot that is grubby, ill-defined and imperfect.
A lot of this, I suspect, is a lot more pragmatic than we would imagine.