9 Any one can devote a place to superstitious uses of his own free will, that is to say, by burying a dead body in his own land. It is not lawful, however, to bury in land which one owns jointly with some one else, and which has not hitherto been used for this purpose, without the other's consent, though one may lawfully bury in a common sepulchre even without such consent. Again, the owner may not devote a place to superstitious uses in which another has a usufruct, without the consent of the latter. It is lawful to bury in another man's ground, if he gives permission, and the ground thereby becomes religious even though he should not give his consent to the interment till after it has taken place. 10 Sanctioned things, too, such as city walls and gates, are, in a sense, subject to divine law, and therefore are not owned by any individual. Such walls are said to be 'sanctioned,' because any offence against them is visited with capital punishment; for which reason those parts of the laws in which we establish a penalty for their transgressors are called sanctions. 11 Things become the private property of individuals in many ways; for the titles by which we acquire ownership in them are some of them titles of natural law, which, as we said, is called the law of nations, while some of them are titles of civil law. It will thus be most convenient to take the older law first: and natural law is clearly the older, having been instituted by nature at the first origin of mankind, whereas civil laws first came into existence when states began to be founded, magistrates to be created, and laws to be written. 12 Wild animals, birds, and fish, that is to say all the creatures which the land, the sea, and the sky produce, as soon as they are caught by any one become at once the property of their captor by the law of nations; for natural reason admits the title of the first occupant to that which previously had no owner. So far as the occupant's title is concerned, it is immaterial whether it is on his own land or on that of another that he catches wild animals or birds, though it is clear that if he goes on another man's land for the sake of hunting or fowling, the latter may forbid him entry if aware of his purpose. An animal thus caught by you is deemed your property so long as it is completely under your control; but so soon as it has escaped from your control, and recovered its natural liberty, it ceases to be yours, and belongs to the first person who subsequently catches it. It is deemed to have recovered its natural liberty when you have lost sight of it, or when, though it is still in your sight, it would be difficult to pursue it.