A monarch dying without testament, is ever understood to will that a monarch should succeed him:
14. But if living he have not declared his will concerning his successor by testament nor otherwise, it is supposed, first, that he would not have his government reduced to an anarchy or the state of war, that is, to the destruction of his subjects; as well because he could not do that without breach of the laws of nature, whereby he was obliged to the performance of all things necessarily conducing to the preservation of peace; as also because, if that had been his will, it had not been hard for him to have declared that openly. Next, because the right passeth according to the will of the father, we must judge of the successor according to the signs of his will. It is understood therefore, that he would have his subjects to be under a monarchical government, rather than any other, because he himself in ruling hath before approved of that state by his example, and hath not afterward either by any word or deed condemned it.
And some one of his children:
15. Furthermore, because by natural necessity all men wish them better, from whom they receive glory and honour, than others; but every man after death receives honour and glory from his children, sooner than from the power of any other men: hence we gather, that a father intends better for his children than any other person’s. It is to be understood therefore, that the will of the father, dying without testament, was that some of his children should succeed him. Yet this is to be understood with this proviso, that there be no more apparent tokens to the contrary: of which kind, after many successions, custom may be one. For he that makes no mention of his succession, is supposed to consent to the customs of his realm.
And a male rather than female:
16. Among children the males carry the pre-eminence; in the beginning perhaps, because for the most part, although not always, they are fitter for the administration of greater matters, but specially of wars; but afterwards, when it was grown a custom, because that custom was not contradicted. And therefore the will of the father, unless some other custom or sign do clearly repugn it, is to be interpreted in favour of them.
And of the males, the eldest rather than the younger:
17. Now because the sons are equal, and the power cannot be divided, the eldest shall succeed. For if there be any difference by reason of age, the eldest is supposed more worthy; for nature being judge, the most in years (because usually it is so) is the wisest; but other judge there cannot be had. But if the brothers must be equally valued, the succession shall be by lot. But primogeniture is a natural lot, and by this the eldest is already preferred; nor is there any that hath power to judge, whether by this or any other kind of lots the matter is to be decided. Now the same reason which contends thus for the first-born son, doth no less for the first-born daughter.
And his brother, if he want issue, before all others.
18. But if he have no children, then the command shall pass to his brothers and sisters; for the same reason that the children should have succeeded, if he had had them. For those that are nearest to us in nature, are supposed to be nearest in benevolence. And to his brothers sooner than his sisters, and to the elder sooner than the younger; for the reason is the same for these, that it was for the children.