[Sidenote: It is essential to a law, that both it and the legislator be known.] 11. It is necessary to the essence of a law, that the subjects be acquainted with two things: first, what man or court hath the supreme power, that is to say, the right of making laws; secondly, what the law itself says. For he that neither knew either to whom or what he is tied to, cannot obey; and by consequence is in such a condition as if he were not tied at all. I say not that it is necessary to the essence of a law, that either one or the other be perpetually known, but only that it be once known. And if the subject afterward forget either the right he hath who made the law, or the law itself, that makes him no less tied to obey; since he might have remembered it, had he a will to obey. [Sidenote: Whence the legislator is known.] 12. _The knowledge of the legislator_ depends on the subject himself; for the right of making laws could not be conferred on any man without his own consent and covenant, either expressed or supposed; expressed, when from the beginning the citizens do themselves constitute a form of governing the city, or when by promise they submit themselves to the dominion of any one; or supposed at least, as when they make use of the benefit of the realm and laws for their protection and conservation against others. For to whose dominion we require our fellow subjects to yield obedience for our good, his dominion we acknowledge to be legitimate by that very request. And therefore ignorance of the power of making laws, can never be a sufficient excuse; for every man knows what he hath done himself. [Sidenote: Promulgation and interpretation are necessary to the knowledge of a law.]