The Patent Act of 1790 set the patent term limit to 14 years and allowed them to be much shorter if the situation called for it, and Article I Section 8. Clause 8 of the Constitution itself calls patents an "exclusive right" for a limited period of time.
So then, we're saying that both the Constitution and the first Congress declared your "private property" to no longer be yours after a limited period of time?
That's quite an... interesting definition of property too, one where the Constitution itself separately defines it from all other property, then gives an explicit reason for allowing you to have any right to it at all, and the reason has nothing to do with it being "your" property and everything to do with the broader benefit to society by promoting "... the Progress of Science and useful Arts".