In Justinian, the seashore is protected like the waters. Water was generally held in common so that anybody could have access to that river. They may not be able to get access to that river through your particular land, although they could get access to it through a public beach that they came on . Now beach is in fact a very common complicated thing. And what happens is the beach constantly moves because if the river starts to expand, then the foliage that is nearby gets wiped out by the water so the bare sand emerges. If it turns out that the river starts to shrink, then the foliage will start to slowly creep into the dry land. So basically beaches are always a thin strip going across the land. Now it has two uses and you have to deal with both of them. One of them, is now it's kind of a convenient land highway next to the river and you certainly don't want to have people blocking that up by claiming that they own the beach because they own the upland. And so this was always treated as land which was part of the commons to which the rule you can never exclude somebody else was applicable to it. But on the other hand in the middle of the storm, you may often have the necessity and then the question is can people take refuge on the beach. Nobody's going to be marching up and down the beach in the middle of the storm, and so if you put a hut on there to allow people to save themselves from the weather that's surely a private use. But the inconvenience with any public use is virtually negligible and then as you often do with respect to this situation you have very powerful temporal limitations. The moment the storm is over you have to take the hut down, because if you don't then everybody's going to start building huts along this particular thing. And it will lose it's value with respect to a transportation system. And so you see a perfect illustration how the Romans were making the following kind of approximation. First we figure out, which is the dominant problem. And surely with rivers, it is the obstruction problem. So you create it as common property. Then you try to figure out how you engraph private uses on this so as to improve the overall efficiency of the system.