I am no historian of early copyright, but my sense is that copyright was pretty broadly referred to as property in the late 1700s and early 1800s -- though if you search for this, you had best search for the term literary property, rather than the somewhat more modern intellectual property. Justin Hughes's Copyright and Incomplete Historiographies: Of Piracy, Propertization, and Thomas Jefferson discusses this well.

This is entirely consistent with treating this kind of property differently from other kinds of property in certain ways -- for instance, treating it as limited in duration, or subject to certain kinds of use by strangers that would not be allowed for land. My point is simply that there is at least a broad and deep legal tradition of treating copyright as property; such a view is no modern innovation, as some have suggested.