This has been a right of nations since the beginning of recorded history. This is an interesting claim to make. For most of recorded history, borders were usu

This has been a right of nations since the beginning of recorded history. This is an interesting claim to make. For most of recorded history, borders were usually uncontrolled except in time of war/threat, and barriers to migration were at least as likely to be imposed at origin as at destination -- people capable of doing labor were an asset, and if they could get away from their current ruler/owner, another ruler would often be happy to take them. European monarchs, for example, would happily poach each others' dissatisfied subjects and even offer them land and religious toleration. And in those times, the rights being exercised over movement were rights of rulers, not rights of nations. The idea of a "nation" as a thing capable of having rights didn't really exist until the 17th century, and was nebulous for some time after.