For many Native nations, land was used according to the seasons and shared by the community. In English law, land became property when it was enclosed, farmed and registered. In his Second Treatise of Government (1689), John Locke wrote that labour makes land property, and used America as his example of land in a natural state. In Pennsylvania, William Penn signed treaties with the Lenape, but in 1737 his sons John and Thomas Penn used the Walking Purchase to take perhaps over one million acres in the Delaware and Lehigh valleys.
Read the source: Locke, Second Treatise, Project Gutenberg · Encyclopedia of Greater Philadelphia, Walking Purchase